Teleconferencing: is video valuable or is audio adequate?

Teleconferencing'. is video valuable or is audio adequate ?

Roger Pye and Ederyn Williams

Many telephone companies and administrations are developing audiovisual teleconference systems; by comparison audiographic systems are receiving a t t e n t i o n a l m o s t exclusively from user organisations. The authors argue that although teleconf e r e n c i n g has had mixed success, w i t h s o m e installations being used o f t e n and judged successful w h i l e o t h e r s a r e n o t , t h e existence of a visual channel showing the participants does not seem necessary. Many other factors l i k e l y t o c o n t r i b u t e t o success are

identified, which, as yet, have received l i t t l e a t t e n t i o n . It is recommended t h a t t h e y be studied through carefully monitored field trials.

Roger Pye is w i t h C o m m u n i c a t i o n s Studies and Planning Ltd, 5 6 - 6 0 Hallam Street, London W l N 5LH, UK, and Ederyn Williams is w i t h the Communications Studies Group, Joint Unit for Planning Research, School of E n v i r o n m e n t a l Studies, Wates House, 22 Gordon Street, L o n d o n W C 1 , UK. The research described in this article was conducted during the period 1970-76 at the Communications Studies Group, University College, London. During that time about 30 people worked at CSG and almost all contributed to work on teleconferencing. Indeed, the majority made substantial contributions, so that continued on page 231

230

Teleconferencing systems, which allow people to participate in a 'meeting' although they are not physically together, have existed for several decades. The oldest studio-based service of which we are aware was an audiovisual one operated from 1935 to 1938 by the German Post Office between public studios in four major cities. ~ The oldest extant studio-based service known to us is a sound-only system operated since 1958 between the headquarters buildings of the Bank of America in San Francisco and Los Angeles} Similarly most telecommunications administrations offer conference call services, by which many telephones may be simultaneously linked; the British Post Office's operator-connected service has existed since 1934. A more recent development is computer teleconferencing, where participants type their statements at a computer terminal connected to a time-shared computer which forwards them to other participants. 3 In this article, we are primarily concerned with the first two types of service - conference television (video) and sound plus still graphic systems (audiographic) - for groups of people in business and government, although some of the findings are also applicable to telephone conference calling. Telecommunications administrations have concentrated mainly on video systems. At present services offering pictures of the same quality as broadcast television are available in the UK, Canada, the USA, Sweden and Australia. Video-telephones and conference systems using similar technology have been developed in the USA, France, the Netherlands, Germany, Japan and the UK. These developments have been costly; it has been estimated that A T & T invested $500 million developing Picturephone. 4 By comparison relatively little effort has been devoted by the administrations to the development of audio teleconferencing. Although many of them provide loudspeaking telephones which can be used for teleconferences, such equipment is not entirely satisfactory for that purpose) Only in France are more sophisticated audio teleconference services being offered publicly; all other such systems have been installed by government agencies and private companies for their own use. In view of the continuing emphasis administrations place on the development of video, despite its higher cost, it is essential to ensure T E L E C O M M U N I C A T I O N S POLICY June 1977

Teleconferencing : is video valuable or is audio adequate? continued from page 2 3 0

adequate acknowledgement to individuals is not possible. The authors can only acknowledge the special contributions made by Alex Reid and Martin Elton as directors of CSG, and the debt which CSG owed to Professor Peter Cowan, director of the Joint Unit for Planning Research, of which the Group is a part. The main sponsors of CSG's teleconference research have been the Long Range Studies Division, Telecommunications Systems Strategy Department, UK Post Office and Civil Service Department. Additional funding has come from the Department of the Environment, Social Science Research Council, Canadian Department of Communications, the US National Science Foundation, the US Departments of Housing and Urban Development and Transportation, General Electric Research and Development Headquarters, and the Nordic Working Party on Conference Telephony. The authors also wish to thank the individuals and organisations who have served as subjects for their work: participant's in experiments; the people who completed meeting record sheets and other questionnaires; and organisations who permitted the evaluation of their teleconference systems. Without their patience and open-minded spirit the work of the CSG would have been impossible. 1 A.A. Reid, 'Needs, technology, effectiveness and impact', Communications Studies Group paper P/71128/RD, 1971. z The Bank of America system, and many others, are reviewed by R.W. Hough, with R.R. Panko, 'Teleconferencing systems: a state of the art survey and preliminary analysis', Stanford Research Institute, Menlo Park, CA, 1976. 3 Computer conferencing is reviewed by L.H. Day, 'Computer conferencing: an overview', Business Planning Group, Bell Canada, Montreal, 1974. " E.M. Dixon and R. Bowers, The Video Telephone, Impact of a N e w Era in Telecommunications, Praeger, New York, 1974. s For example, Communications Studies Group Research for the Nordic Working Party on Conference Telephony found that audio systems which have fully open audio channels are preferred to those in which the sound is either manually or automatically switched (Ederyn Williams, The comparison of four types of audio conference systems: attitudes and decision making', Communications Studies Group paper E/74307/WL, 1974). Christie (B. Christie and M. Elton, 'Research on the differences between telecommunication and face-to-face communication in business and government', Communications Studies Group paper P/75180/CR, 1975) showed that participants value speaker identification. Many Open University students found the standard UK continued on page 2 3 2

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that a video channel showing moving pictures of the participants is necessary.

Success and failure Evidence on the future of teleconferencing is mixed. Theoretical analysis suggests that it has a great future, either as a travel substitute, or in its own right, and the extent of development work suggests that many believe this. However, several organisations have had less than complete success when they have tried to introduce teleconferencing. Even so, there is no evidence that video systems are more successful than audio ones. Consider, for example, the experience of a UK government department. 6 A video conferencing system was installed in studios in two buildings on opposite sides of the River Thames. Each studio was equipped with a single 24 inch black and white television receiver which displayed up to three remote participants. Although the service was available to the thousands of employees in the buildings, it was seldom used. After a few teleconferences by two groups, use ceased completely and the system was removed. In sharp contrast is the experience of N A S A (the US National Aeronautics and Space Administration). A system has been operational for almost ten years, and now consists of 30 studios at the sites of N A S A and its contractors, which carry about 30 000 person-meetings per year. Since the system is audio supplemented by rapid facsimile, costs are lower than for video and the estimated savings for N A S A are approaching halfa million dollars each year. 7

Factors contributing to success and failure The factors which may be expected to influence the success of a teleconference system fall into four main groups. The first comprises the consequences of the nature o f the transmission channel: the extent to which the transmitted information permits satisfactory conduct of meeting tasks; the extent to which users accept communication via the channel; the cost of the channel; s the quality and fidelity of the channel; and the quality of graphics facilities. The consequences of studio and terminal arrangements constitute the second group, ie the ease of accessing and booking terminals and studios, and the comfort and design of terminals and studios. In the third group are the consequences of the nature of user organisations: the extent to which the staff are naturally well disposed towards teleconferencing; the extent to which their meetings are particularly suited to teleconferencing; the attractiveness of the travel alternatives; and the extent to which organisational structure and associated management procedures are favourable to teleconferencing (the extent of intersite collaboration, for example). Finally, there are the consequences of the support provided to the service: regularity of maintenance, the extent of publicity, the extent of training given to users, and the manner in which the service is introduced. In addressing the importance of a visual channel, we are concerned with the first group of factors; and especially the first three. 9 Nevertheless, the others are undoubtedly important and may well explain the mixed success of teleconferencing. Unfortunately, there is at present insufficient evidence for an assessment of their relative importance.

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Teleconf erencing." is video valuable or is audio adequate? continued from page 231 Ioudspeaking telephone unacceptable for small group tutorials (S. Holloway and S. H a m m o n d , 'Tutoring by telephone: a case study in the Open University', Communication Studies Group paper P / 7 5 0 2 5 / H L , 1975). 8 B. Christie, 'A summary of the DoE teleconferencing experience', Communications Studies Group paper P/74280/CR, 1974. 7 S.W. Fordyce, ' N A S A experience in telecommunications as a substitute for transportation', unpublished paper, NASA, Washington, DC, 1974. 8 An expensive public system is less likely to be used and an expensive private system is more difficult to judge to be a success. 9 The factors are not wholly independent of each other. One interdependence that is important to the subject of this paper is between cost and accessibility. As video systems are more expensive they require more frequent use to be justifiable and/or profitable. As a result, they are usually public services with studios in city centres. Such studios are inevitably more remote from users than those of private, in-house systems. 10For example, the extent to which it affects the quality of problem solution, or amount of attitude change. 11 The advantages and disadvantages of laboratory experiments are further discussed by J. Short, 'The use of the laboratory experiment in the evaluation of the effectiveness of telecommunications meetings as substitutes for face-to-face meetings', Communications Studies Group paper E / 7 2 1 5 0 / S H , 1972. 12j. Short, E. Williams, and B. Christie, The Social Psychology of Telecommunications, John Wiley and Sons, London, 1976. B. Christie and M. Elton, 'Research on the differences between telecommunication and face-to-face communication in business and government', Communications Studies Group paper P/75180/CR, 1975. E. Williams, 'Experimental comparisons of face-to-face and mediated communication: a review', Psychology Bulletin, 1977 (in press). R. Pye, 'Communications effectiveness and efficiency' in Technology Assessment of Telecommunications~Transportation Interactions: Volume II, Detailed Impact Analysis, Stanford Research Institute, Menlo Park, CA, 1976. 13j. Short, 'The effects of medium of communication on persuasion, bargaining and perceptions of the other', Communications Studies Group paper E / 7 3 1 0 0 / S H , 1973. 14 In this experiment, as in all others, the effects of the media on task outcome were compared by statistical tests. All differences mentioned in this and the continued on page 233 aposition in relation to proposer and seconder.

232

Effectiveness of teleconference media Laboratory experiments are the primary method of assessing the relative effectiveness of media, that is the extent to which the medium used affects the outcome of the meeting's task. ~° This approach is essential because control, replication and measurement are necessary to achieve valid comparison, and these can only be obtained with any certainty in laboratory experiments, t' Since there are recent comprehensive summaries of the research on the effectiveness of communication by various media t2 we shall summarise only two experiments and the overall results. Short ~3 brought 72 civil servants into the laboratory where they held two ten-minute conversations in pairs. During the conversations they communicated face-to-face, by an audio link, or by one of two video links (which differed only slightly). They argued about controversial issues, such as 'heart transplant surgery is a waste of money', on which it had been previously established, by means of a questionnaire, that they disagreed. After the discussion, they again rated their opinion on the item, as well as their opinion of the other person. From the differences between initial and final opinion, the amount of opinion change could be calculated. The amount of change by each medium was (with the figures adjusted so that face-to-face is 100%): face-to-face, 100%; video (2 variants), 198%: audio, 221%. There was clearly more opinion change by audio and video than face-to-face. ~4 This result has been repeated several times. On the other hand, communication medium did not greatly affect the participants' opinions of each other. A quite different kind of experiment was carried out by Williams. ~5 Forty five groups of four people (again civil servants) met face-toface, or by a video or audio link. When teleconferencing was used, two people were at each end. For thirty minutes these groups "brainstormed', attempting to generate ideas for improving travel in the UK. Each idea was noted by the 'secretary' of the group as soon as it had been proposed and seconded, together with the names of its proposer, seconder, and any dissenters. The results showed that the media did not affect the number of ideas generated in thirty minutes, or the originality and quality of the ideas. However, the media did result in the formation of different coalitions. As Table I shows, with the teleconference media, proposer and seconder tended to be located at the same end of the link significantly more frequently than chance expectation (chance equals 100% in Table 1). With audio conferencing, there was also a tendency for dissenters to come from the opposite end to both proposer and seconder. Table 1. Influence of teleconference media on coalition and dissent. Proposer and seconder On same side Audio Video

120% 118%

Audio Video

69% 95%

On opposite sides 90% 91% Dissentera

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162% 109%

POLICY June 1977

Te/ecolferencing : is video ra/uable or is audio adequate ?

In addition, when using audio, participants rated the person at the same end of the link as more intelligent, constructive, competent, trustworthy and sensible, and as less impersonal, boring and unreasonable than the people at the far end. These two studies illustrate the experimental techniques that have been used. However, they are exceptions: few experiments have discovered significant consequences resulting from the use of teleconference media for business-type meeting tasks. In the UK, the USA and Canada, numerous carefully conducted experiments on information transmission, problem solving, group decision making and interviewing have found all vocal media to be very similar in effectiveness for these tasks. It is initially surprising that so few studies have found media effects. Literature on person-to-person communication discusses extensively the importance of non-verbal signals: eye-gaze, gestures and facial expression. ~6 Even more surprising is the finding that when the media differ, video is usually more like audio than face-to-face, since video systems transmit many of the non-verbal signals that audio omits. In view of the weight of evidence it would be naive to persist in thinking that video is 'just like face-to-face' and vastly different from audio. Indeed non-verbal channels may not have as crucial a role as initially supposed, possibly for the following reasons:

•

•

•

continued from page 232 subsequent section are statistically significant to the level of p =. 0.05. is E. Williams, 'Coalition formation over telecommunications media', European Journal of Social Psychology, Vol 5, 1975, pp 503-507. le M. Argyle, 'Non-verbal communication in human social interaction', in R.A. Hinde, Non-Verbal Communication, Cambridge University Press, 1972. 17 S. Duncan, 'Some signals and rules for taking speaking turns in conversations', Journal of Personality and Social Psychology, Vo123. pp 2 8 3 - 9 2 . la For example, face-to-face people greet each other with a handshake, nod, smile, and 'hello', but on the telephone the 'hello' may stand for all the other greetings, whose absence does not affect the outcome. 19 Short, Williams and Christie, op cit, Reference 12, discuss this concept extensively.

Non-verbal signals and the associated speech are highly redundant. Duncan ~7 listed seven different verbal and non-verbal cues that signal that a person is about to stop speaking. When using a medium which omits some of them, listeners may shift their attention to the others. ~8 When using a teleconferencing medium, people may change their behaviour. If they cannot be seen, they may use the verbal channel as a substitute for the non-verbal. Thus they might say 'I agree' instead of nodding, or 'five feet long' instead of stretching out their arms. Non-verbal cues do not have a constant meaning: their meaning depends on how they are used. Facial expression may be friendly or unfriendly: hand gestures may help or distract from speech. If such positive and negative effects normally counter each other, removing the visual channel would have little effect.

It seems, then, that non-verbal cues may not be as crucial as first supposed. Instead, it seems that the major difference between the media may lie in the 'social presence' that they provide. ~9 Face-toface. people have a feeling of closeness and contact which is reduced substantially by the use of either video or audio. That experiments frequently show video and audio teleconferences to be like each other, but different from face-to-face meetings, is quite consistent with this theory.

Acceptability of the media: attitude research In the above section, it is argued that the presence of a visual channel increases the effectiveness of a teleconference system for only a few tasks. Such a finding would be relatively unimportant if people perceived video to be more effective for tasks, or if they had a strong preference for using it. Users of four real (not laboratory) teleconference systems were

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233

Teleconferencing: is video valuable or is audio adequate? F i g u r e 1. Responses of users of four t e l e c o n f e r e n c e s y s t e m s (Confravision,

Completely Completely unsotisfoctory sohsfoctory

Completely sotisfoctory

the R e m o t e M e e t i n g Table, the Bell Canada C o n f e r e n c e Television system and the U n i v e r s i t y of Q u e b e c audio c o n f e r e n c e system) to the question: ' H o w satisfactory do you think you w o u l d find the t e l e c o n f e r e n c e for the f o l l o w i n g activities?'

Giv=ngor rece=~mg inf0rmotion

+6 I

Completely unsotlsfQctory

+ __~V2 I

I

1

=

Generating ideas

'7

2831

I __

Ziv

2026

1

L

I

I

20 See Short, Williams and Christie, ibid, for further details of the studies. 21 There are exceptions; for example, Short's finding, discussed above, that there is more attitude change via audio than face-to-face, is contrary to the belief demonstrated in Figure 1 that most people see audio as less satisfactory than faceto-face for persuasion. However, this begs the question 'Satisfactory for whom?' One person's gain may be the other's loss. 2z B.C. Champness, 'Attitudes toward person-person communcations media', Human Factors, Vol 15, 1973, pp 437448. 23 This finding has been confirmed in work by CSG and by others. See, for example, J.H. Kollen and J. Garwood, 'Travel communications tradeoffs: the potential for substitution among business travellers', Business Planning Group, Bell Canada, Montreal, 1975, and F.W. Snyder. 'Travel patterns: implications for new communications facilities', Bell Laboratories, Holmdel, NJ, 1971.

234

,7

a

J

39 4O Borgomlng 47

Exchongmg Opmlons

1912' '71vA I

I

I

]

]

2 3

37641 ~ ~I 39 Getting to know someone

Problem solving

27 •

i

Persuos~on

Asking queshons

26O Source: B. Champness, 'The assessment of users' reactions to Confravision: analysis and conclusions', Communications Studies Group report E/73250/CH, 1973; E. Williams and S. Holloway, 'The evaluation of teleconferencing: report of a questionnaire study of users' attitudes to the Bell Canada conference TV system', Communications Studies Group report P/74247ANL, 1974; H. Thomas and E. Williams, 'The University of Quebec audio conferencing system: an analysis of users' attitudes', Communications Studies Group report P/75190/'TH, 1975; B.C. Champness, 'Remote meeting table: preliminary report of a questionnaire study', Communications Studies Group paper W/72310/CH, 1973.

I

27

40

University of Quebec Bell Conodo

z~ &

51

Confrovision RemotemeetinG toble

asked how satisfactory they perceived their system to be for a variety of meeting tasks. The results are shown in Figure 1. 20 The figure shows that all the media were perceived to be more satisfactory for some tasks than for others. In general, users' perceptions of the effectiveness of teleconferencing for meeting tasks is close to the objective effectiveness investigated in the laboratory experiments. 21 However, there is relatively little difference between the media for individual tasks, video seldom being perceived to be more effective than audio. Indeed, video seems consistently better than audio only for those tasks for which both were rated as relatively unsatisfactory. Champness 2z conducted a study in which civil servants had conversations face-to-face, by video and by audio, and then rated the extent to which the media could be described in terms of a number of semantic differential scales, which are an established method of measuring emotional response. The scales were simplified into a few dimensions by factor analysis. Three interpretable factors emerged. The first was simple evaluation: good-bad, meaningful-meaningless, successful-unsuccessful. Face-to-face was clearly rated at the 'good' end of the scale, video was neutral, and audio was distinctly 'bad'. The second factor was aesthetic judgement: beautiful-ugly, colourfulcolourless, interesting-boring. Face-to-face and video were considered equally "beautiful', while audio tended towards 'ugly'. Finally, there was a privacy factor, which was really just a single scale - publicprivate. Audio and face-to-face were considered 'private' while video was rated as distinctly +public'. It seems, then, that emotional responses to these three media differ considerably: users and potential users have a strong general preference for video over audio. 23 However, although users prefer to use video rather than audio, there is evidence that the preference may be relatively unimportant in choices between travel and teleconferencing. After briefly using either a video or an audio system, 96 managers and civil servants had a hypothetical meeting described to them. Aspects of its description were varied systematically: the meeting would involve bargaining or it would involve discussing ideas; it would be with acquaintances or with strangers: travel for a face-to-face meeting would take half-an-

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P O L I C Y June 1 9 7 7

Telecolferencing : is video valuable or is audio adequate ?

hour. one hour, two hours or four hours. They were then asked if they would choose to travel, or to use the telecommunications system they had just experienced, in order to conduct such a meeting. 24 It was discovered that the telecommunicate/travel choice was strongly affected by the task which was described, by the degree of acquaintance specified, and by the length of travel involved. However, the particular teleconference system experienced did not affect the choice: participants were equally likely to choose to telecommunicate if they were offered audio or if they were offered full video. A subsequent experiment 2~ did show an effect of medium with video attracting more choices in comparison to travel than did audio. However, this method of measuring attitudes usually shows relatively little difference between audio and video. Hence although when they are asked to compare video and audio as such, people tend to have strong emotional preferences for video over audio, and even think it a worthwhile substitute for face-to-face, when they consider using teleconferencing for a real meeting, other factors must be taken into account. The task, level of acquaintance of participants, cost, inflexibility of booking, loss of travel benefits and many other factors may affect the decision. Moreover there are strong indications, from Christie's work, that these other factors are more important than the presence or absence of a visual channel.

Proportion of meetings suitable for each medium

2,=B. Christie and S. Holloway, 'Factors affecting the use of telecommunications by management', Journal of Occupational Psychology, Vo148, 1975, pp 3-9. ZSB. Christie, 'Travel or telecommunicate? Some factors affecting the choice', Communications Studies Group paper E/75030/CR, 1975. 26 For evidence of these benefits, see R. Pye, 'Communications effectiveness and efficiency', in Technology Assessment of

Telecommunications/Transportation Interactions: Volume II, Detailed Impact Analysis, Stanford Research Institute. Menlo Park, CA. 1976. ZrFor example, Stapley reported that many users of an audio system were favourably surprised as to its effectiveness when they used it (B. Stapley, 'The second report of the Remote Meeting Table questionnaire', Communications Studies Group paper P/73045/CH, 1973).

The principal purpose of investigating the effectiveness and acceptability of teleconference media was to determine the proportion of meetings which are currently face-to-face but seem suitable for transfer to teleconferencing. Our assessment is inherently conservative: we estimate the proportion of meetings which consist only of tasks of which the outcome would not be affected if the meeting were conducted as a teleconference. In practice, people may be prepared to suffer from loss of effectiveness in order to gain the other benefits of teleconferencing. In addition, in the longer term, generated traffic, that is new meetings stimulated by the availability of teleconferencing, may be much more important than substitution of teleconferences for existing meetings. However, substitution seems to be the main initial usage, and is probably essential for the introduction of a new system. It is important to stress that our approach is neither normative nor predictive. Teleconferencing has a number of advantages (cheapness, brevity, speed, specificity, regularity 26) over face-to-face meetings which should be taken into account when assessing how people should choose between media. Prediction would be premature, since some of the benefits have not been quantified and the tradeoff between the various advantages and disadvantages is unknown. Moreover, potential users are still relatively uninformed, though we would expect that with experience their choice between the media would gradually come to accord with our allocations. In choosing this approach we avoid the problems inherent in one that has been used elsewhere, in which various media are described to people who are then asked to assess which of them would have been adequate for a recent meeting. Most people have never used teleconference media, know little about their effectiveness, 27 and are not in a position to give a valid answer. One could rely upon answers to

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235

Teleconferencing: is video valuable or is audio adequate?

such a question only if the population concerned had considerable experience with all the media. As no such population exists, C S G used an approach based on an investigation of the nature of the meetings. The first method involved the use of the 'Contact Record Sheet'. :8 This questionnaire was issued to over 6000 civil servants subject to the Relocation of Government Review which recommended the dispersal of over 30 000 civil servants from London. 29 The questionnaire asked details of a recent face-to-face meeting involving people from outside the respondents' 'block-of-work' (a small organisational unit unsuitable for further subdivision). In particular, it asked whether the meeting could have been held by telephone and, if it could not, the respondents' primary and secondary reasons for making that judgement. On the basis of these reasons, the meetings were allocated to classes: meetings suitable for being conducted by audiographics (ie audio systems enhanced to carry graphics): meetings suitable for being conducted by video but not by audiographics: and meetings not suitable for transfer. Details of the allocation process are shown in Figure 2. Its results are summarised in Table 2, together with those from the survey by Goddard and Morris 3° o f the face-to-face meetings o f office workers in organisations that had relocated from London, which used almost exactly the same methodology. More of the meetings recorded in decentralised offices were said by respondents to be substitutable, probably because more of them were brief and involved only shortdistance travel. Had further travel been necessary, many of the twoperson contacts would have been by telephone, and so would not have been included in the survey.

2a Communications Studies Group Interim Report May 1972, Report B/72145/RD. 2s The Dispersal o f Government Work from London, HMSO, London 1973 (The

Hardman Report). zo J.B. Goddard and D. Morris, The Communications Factor in Office Decentralization, Pergamon Press, Oxford, 1976.

4

More than 12 participants Inspection, lecture, or interview t N~ Friendly relations primary

I

t

I

I

..............................................33.8% .........................

I Yes I . l % ~

Range :

262-413%

t No Courtesy primary

t No Other reasonsprimary t No Background information primary

NO Assessing reactions primary ) NO

F i g u r e 2. A l l o c a t i o n of m e e t i n g s to classes of s u i t a b i l i t y on the basis o f the C o n t a c t Record S h e e t study.

Persuasion primary The circles represent a 50% split of meetings for which that was the primary reason for holding it face-to-face. For example, 50% of the meetings held because of the need to 'gather background information' are allocated to the audiovisual type. The ranges of percentages of those meetings are obtained by varying the splits. Thus 26.2% of meetings are of the face-to-face type if all meetings to gather background information are so allocated. Source." Communications Studies Group,

J Yes9.2 J Y

e

s

l

S

l

~

4.",",:,", :.;-'::,,',".',,,":;."~,] Audiovisualtype:

J Yes 3 . e % J / Yes 2 8 ° / o J

.

_j;,;:,;,,:~.::,.r,,c,v

,

231% Range: 66-398°/°

"~,""):":"':':":',;,:"

t NO Groups primary

i NO Documents primary No I

AUod;°~rophictype :

Security primary tNo

Range : 31 .I -49.1%

I Inconvenienceof handset primary

tNo J

More than two participants

I

i No Telephone/ telex satisfactory

Yes 3 o '/0

"-

--J~-J~-J~-~

Interim Report May 1972, B/72145/RD.

236

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POLICY

June 1977

Teleconferencing: is video valuable or is audio adequate ? Table 2. Results of surveys using the 'Contact Record Sheet' methodology.

Source: Communications Studies Group, Interim Report May 1972, Report B/72145/RD. J.B. Goddard and D. Morris, The Communications Factor in Dispersal, Pergamon Press, Oxford, 1976.

Number of meetings Suitable for: Face-to-face Video Audiographics Telephone

Civil service 6397 26--41% 7-40% 31 --49% 3%

Decentralised offices 344

22% 27% 38% 13%

Table 3. Effect of medium on meeting tasks.

For the types of tasks in parentheses, evidence is more sparse, so the allocations are inevitably less reliable.

Source: E. Williams, 'A summary of the present state of knowledge regarding the effectiveness of the substitution of faceto-face meetings by telecommunicated meetings: type allocation revisited', Communications Studies Group paper P/74294/~NL, 1974.

31 R. Pye, B.G. Champness, H.A. Collins, and S. Connell, 'The description and classification of meetings', Communications Studies Group paper P/73160/PY, 1973. 32 For some tasks, assessments have to be somewhat tentative, since insufficient evidence is available, and in no case can we be so certain of the accuracy of the assessment that further information might not change it. 33 S. Connell, 'Report of the 1973 Office Communications Survey', Communications Studies Group report P/74067/CN, 1974, and "The Office Communications Survey: additional analysis', Communications Studies Group report P/74225/CN, 1974.

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Outcome of meetings is:

Faidy definite decision

Tentative decision

Different by audio or video from that face-to-face

Inspection of fixed objects

Conflict; Negotiation; Disciplinary interview; (Presentation of report).

The same by video and faceto-face, different by audio

Forming impressions of others

Giving information to keep people in the picture

The same by audio, video, and face-to-face

Problem solving; Information seeking; Pot icy decision making

Discussion of ideas; (Delegation of work)

The Contact Record Sheet surveys gave useful initial estimates of the proportions of face-to-face meetings that are suitable for transfer to teleconference media. However they are less satisfactory than recent estimates which have been based on the psychological experiments and on the D A C O M (description and classification of meetings) study. 3~ The D A C O M study asked managers to describe the function of and activities at a recent meeting. A set of key phrases was extracted and a second group of managers was then asked the extent to which those key phrases applied to a meeting. The ratings were reduced by factor analysis to twelve independent dimensions of meeting function and activity. The effect of using teleconference media on the outcomes of those task types was then assessed on the basis of laboratory experiments. Table 3 shows the task types classified into three groups: those for which the outcome is unaffected whichever vocal medium is used; those for which the outcome face-to-face is the same as that by video, but different from that by audio; and those for which the outcomes by video and audio are both different from that face-to-face. 32 The 12 descriptors derived by the D A C O M study and shown in Table 3 were used in the following way to estimate the proportion of meetings suitable for substitution. In the 1973 Office Communication Survey23 questionnaires were administered to office employees in 145 office establishments, sampled at random from three regions of England. Each subject was asked to record details of up to ten meetings that involved someone from outside his/her own department during a five-day period: 3160 meetings were recorded. One of the questions asked the respondent to rate the extent to which each of the 12 descriptors applied to the meeting. On the basis of the ratings, the meetings could be assessed for their suitability for teleconferencing.

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Telecolferenchlg: is video valuable or is audio adequate?

These data were used by Tyler, Cartwright, and Collins 34 who corrected for the bias that large meetings are more likely to be reported than small meetings, and, using assessments similar to those in Table 3, estimated that of the present business meetings held in the United Kingdom 45% were suitable for being conducted by audio, 8% were suitable for being conducted by video, and 47% required face-to-face communication. 35 These three studies of office-workers all show similar results: a considerable proportion of meetings that are currently face-to-face could be conducted as teleconferences, mainly just with audiographics. However, studies of single organisations have had divergent results. Analysis by Collins of a 'Contact Record Sheet' type question administered to 233 people in an engineering consultancy and a national industry indicated a much smaller proportion of substitutable meetings? 6 When a D A C O M - t y p e question was administered to a small group of US office workers, considerably more meetings seemed suitable for teleconferencing? 7 Although methodological differences and problems probably exaggerate the divergences, these results strongly suggest that particular organisations may be either considerably more suited or considerably less suited to teleconferencing than is normal. M. Tyler, B. Cartwright, and H.A. Collins, 'Interactions between telecommunications and face-to-face contact: prospects for teleconference systems', Long Range Intelligence Bulletin 9, Telecommunications Systems Strategy Department, UK Post Office. 3s This study used the most satisfactory methodology on a large number of meetings, so strong reliance may be placed on its results. 36 H. Collins, 'Telecommunications impact model: stages I and II, December 1972', Communications Studies Group report P/72356/CL, 1972. 37 R. Pye, 'Analysis of the data collected by the survey of GECC', Communications Studies Group paper P/73280/PY, 1973. 3a In fact, there is evidence that the audio teleconferences are shorter than face-toface meetings (J. Craig and G. Jull, 'Teleconferencing studies: behavioural research and technological implications', paper presented at the Seventh International Symposium on Human Factors in Telecommunications, Montreal, 1974), though there is no comparable evidence for video. 39 This formula assumes that travel time is wasted and that its costs must be borne by the employer. If the employee travels in his/her own time or works while travelling, then the duration of travel time should be reduced. 40 For example, that it is equivalent to part of the cost of travel to a meeting, so that both may be neglected. 4~ M. Elton, and R. Pye, 'Travel or telecommunicate? Comparative costs', Communications Studies Group paper P/73166/EL. 1973. 42 A. Cook, 'A more detailed study of the costs of travel and telecommunication', Communications Studies Group paper P/75008/CK, 1975. 34

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Cost comparisons Direct comparison of the costs of travelling to a meeting with those of holding it as a teleconference is difficult. Costs of travel depend on the number of people travelling, on the value of the time so spent, and on fare and subsistence costs. Costs of teleconferencing depend on the duration of the meeting and on tariffs, which in turn depend on the cost of equipment, its utilisation and on the policy of the supplier company. If it is assumed that the duration of the meeting is the same by each medium, 3s so that the cost of the time so spent is constant and can be neglected, costs may be expressed as follows: Cost of travelling to a meeting 39 = [Number of people travelling to the meeting] x [fare cost + subsistence cost + (value of travel time) x (.journey duration)] Cost of teleconferencing = (meeting duration) x (tariff per hour) + (cost of travel to studios) x (number of people travelling to studios) When this is expressed algebraically and some assumption is made about the cost of travel to studios, 4° it can be seen that teleconferencing is cheaper than travel if meeting duration divided by number of people travelling is less than a critical value, which, in general, depends on distance, on the value of travel time, and on tariffs. 4~ Using the same approach, Cook 42 compared the present cost of travel by the cheapest mode (car, train or aeroplane, according to distance) with the costs of audio and video systems that are used for 60% of the working week and are based on existing technology, notably coaxial cable for video transmission. The studio equipment for the audio was relatively expensive (£4000) and that for video relatively cheap (£20 000), compared to most present systems. Cook showed that, for current UK costs, use of video was cheaper than travel if the test statistic (duration of meeting in hours)/(number of travellers) was less than 3.2 when travel time was costed at £2.50 per

T E L E C O M M U N I C A T I O N S POLICY June 1977

Teleconferencing : is video valuable or is audio adequate ? Table 4. Critical values of the test statistic (duration)/(number of travellers) for choice between travel and audio. Cost of travel time (£/hour) 2.50 5.00 10.00 20.00

43 B. Stapley, 'Cost considerations of the R MT within the Scottish Office', Communications Studies Group paper W/73297/ST. 1973. '~R. Pye, "Travel and telecommunications costs', in Technology Assessment

and Telecommunications/Transportation Interactions: Volume II, Detailed Impact Analysis, Stanford Research Institute, Menlo Park, CA, 1976. 4s Kollen and Garwood, op cit, Reference 23. ,=6 Pye, op cit, Reference 44. 47The New York Telephone Company operates a service between New York City and Albany at a tariff equivalent to $ 1 . 2 3 per mile per hour and the UK Post Office's Confravision system is tariffed at about £ 1 - 0 0 per mile per hour (averaged over all routes). By comparison, PMS is tariffed at about $ 0 . 2 4 per mile per hour over distances of less than 1000 miles and $O-12 per mile over distances of between 2 0 0 0 and 2 5 0 0 miles.

Distance (miles) 25 1.4 0.8 0.5 0.2

100 0.6 0.4 0.2 0.1

200 0 J, 0.3 0.2 0-1

hour. 2.2 at £5.00 per hour, 1.3 at £10-00 per hour, and 0.7 at £20.00 per hour. Thus if travel time is valued at £10 per hour it would be cheaper for three people to travel to a three-hour meeting, but cheaper to use video if four would have to travel. These critical values are approximately valid for 25 to 450 miles, although video is somewhat less attractive at the shorter and longer distance. Audio is very much cheaper than video and in most cases is also cheaper than travel. The comparison is more difficult to summarise than that for video because it is more dependent on the distance that would have to be travelled. Critical values for some distances and valuations of travel time are shown in Table 4. For example, if travel time is valued at £10-00 per hour, use of an audio teleconference system would be cheaper than travel by two people for 25 miles if the meeting lasted less than an hour, but not if it were longer. Clearly, for all but a few meetings use of quite sophisticated audio systems is cheaper than travel. Audio systems need be used only occasionally to be justified on cost grounds: Stapley 43 showed that a link between London and Edinburgh was justified on just fare and subsistence savings if one three-person trip and one four-person trip were avoided each month. Identical figures have been obtained for comparisons of the costs of intercity travel in the USA with the costs of studio-based audio teleconferencing." The comparison is even more favourable if either cheaper terminal equipment is used or if dialled lines are used instead of private circuits, unless the latter are heavily used. The comparisons indicate that audio is generally cheaper than travel but that video has a cost broadly comparable to that of travel, being cheaper for some meetings but not for others. In order to investigate the actual proportion of meetings and trips for which use of video would be cheaper, it is necessary to know the distribution of the test statistic (duration)/(number of travellers). Unfortunately such data have been collected in only one survey, conducted by Bell Canada. 45 Those data have been used to compare the costs of a service such as AT&T's Picturephone Meeting Service (PMS) with the costs of travel, assuming that US values of the test statistic would be similarly distributed to Canadian ones. 46 Use of PMS on the routes New York-Chicago, New York-Washington, DC and Chicago-Washington, DC would be cheaper than travel for the percentages of trips shown in Table 5. It should be remembered that PMS has a much lower tariff than other video services, being based on the estimated costs, in 1975 dollars, of 1985 technology, including bandwidth reduction to reduce the cost of transmission. 47 Thus, even allowing for technological advances, video is cheaper than travel for only a relatively small proportion of present trips.

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Teleeolf erencing : is video valuable or is audio adequate ? Table 5. Percentage of a sample of business trips for which PMS (video conferencing) would be cheaper. Route

Value of travel time (S/hour)

New York-Chicago New York-Washington DC Chicago-Washington DC

Value

,8 This should not be taken to imply that any vocal teleconference medium, with any design, will be equally effective. Imperfections such as poor sound quality, howl-around, manual switching or severe voice-clipping could yet be shown to influence effectiveness strongly. 49Tyler, Cartwright and Collins, op cit, Reference 34. ~o Connell, op cit, Reference 33. $1 Elton and Pye, op cit, Reference 41.

Table 6. Combined allocation of business meetings that are currently face-to-face. Suitable for

Audio only Audiographics Video Face-to-face

22% 17% 2% 59%

S o u r c e : M. Tyler, B. Cartwright, and H.A. Collins, 'Interactions between telecommunications and face-to-face contact: prospects for teleconference systems', Long Range Intelligence Bulletin 9, Telecommunications Systems Strategy Department, UK Post Office.

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of a visual

}

0

5

4%

5%

10 6%

20 9%

40 16%

channel

The research reviewed casts considerable doubt on the value of a visual channel to enable participants in business teleconferences to see each other. The experiments show that many tasks can be conducted by vocal media without affecting the outcome. 48 Moreover, although tasks which involve a greater amount of interpersonal interaction are so affected, it is seldom the case that video would give the same outcome as face-to-face when audio would not. Indeed for some tasks it can be argued that audio is the superior channel. As a result, when existing meetings are assessed as to their suitability for being conducted as teleconferences, many appear suitable for being conducted by audiographics (the outcome would not be affected and potential users perceive audio to be effective) but few that appear unsuitable for conduct by audiographics are entirely suitable for conduct by video. Similarly, although most people say they would rather use video than audio, seeing the former as more attractive and its use as more enjoyable, available evidence suggests that the preference would not materially influence choices between teleconferencing and travel. Factors such as the nature of the task, acquaintance with other participants and length of travel appear to influence those decisions more strongly. Finally, although the cost of using audiographics compares very favourably with the cost of travel, use of video would usually be more expensive than travel, both now and in the near future when technical developments such as bandwidth compression have reduced the cost of long-distance transmission. Thus the evidence on effectiveness, on acceptability and on costs is fairly favourable to audiographic teleconferencing as a substitute for face-to-face communication, but relatively unfavourable to video. The only study which has combined all three lines of evidence into a single estimate is that by Tyler, Cartwright and Collins. 49 This takes as its basis the Office Communications Survey sample of meetings 5° and adds the "suitability' information in Table 2. Using Elton and Pye's 51 method of cost comparison, but incorporating assumed 1990 costs (which anticipate technological advances and so are more favourable to teleconferencing) they estimated the division between meetings shown in Table 6. Although these are the best estimates currently available, there is no doubt that they can be further improved, by including other, so far unquantified, factors such as accessibility. At the beginning of this article seventeen factors were hypothesised to affect the success of teleconferencing. Only the three discussed here - the extent to which use of media achieves the same outcome as would a face-to-face meeting, attitudes to the media, and system cost - have been extensively researched. For the others, little knowledge

T E L E C O M M U N I C A T I O N S POLICY June 1977

Telecolferencing: is video valuable or is audio adequate?

sz For example, the accessibility of audio studios is likely to be higher since their cheapness would allow provision to smaller numbers of users. s3 We have been concerned here with the use of teleconferencing for business meetings. However, similar findings have been obtained in telemedicine experiments. D.W. Conrath et al (IEEE Transactions on Communications, Vol COM-23, No 10, October 1975, pp 1119-1125) reported that face-to-face diagnosis was superior only for detecting secondary ailments and that video and audio were equally effective. Thus audio may be wholly adequate for a wide range of interpersonal tasks.

exists. However, this does not greatly alter the conclusions regarding video and audio. Some of the factors are irrelevant to this crucial design decision while others, if important, tend to favour audio over video. 52 We are confident that further research will not completely overturn our conclusions that audio is adequate, and video is usually not valuable for business meetings. 53 Only fundamental technological breakthroughs, which reduced the cost of video to negligible amounts, would alter our conclusions. Nevertheless, further research on the other factors listed at the beginning of this paper could be extremely valuable in guiding the introduction of teleconferencing, whether audio or video, to successful use. The other factors can only be studied when systems are in real use. The variables of interest cannot be subjected to either controlled laboratory experiment or 'desk' study. Unfortunately, few actual systems have been fully evaluated and most of those have been evaluated in isolation. Knowledge about other factors can only be improved by gathering sufficient information about the use of many systems to be able to deduce which factors contribute most to success. For comparison to be possible, organisations which use or provide the services will have to be very objective about the extent to which they are successful. If success is applauded without investigation, or if failure is deliberately concealed, then progress may be slow, resources may be wasted and a service with considerable potential may never fully mature.

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