The effect of parent education program for preschool children with developmental disabilities: A randomized controlled trial

Research in Developmental Disabilities 56 (2016) 18–28

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Research in Developmental Disabilities

The effect of parent education program for preschool children with developmental disabilities: A randomized controlled trial Cynthia Leung a,∗ , Stanley Chan b , Tiney Lam c , Sharon Yau d , Sandra Tsang e a b c d e

The Hong Kong Polytechnic University, Hong Kong Heep Hong Society, Hong Kong The Hong Kong Polytechnic University, Hong Kong The Hong Kong Polytechnic University, Hong Kong The University of Hong Kong, Hong Kong

a r t i c l e

i n f o

Article history: Received 29 January 2016 Received in revised form 18 May 2016 Accepted 18 May 2016 Number of reviews: 2 Keywords: Parent training Developmental disability Preschool children

a b s t r a c t Aim: This study aimed to evaluate the efficacy of a parent education program, the Happy Parenting program, for Chinese preschool children with developmental disabilities. Methods: This study adopted randomized controlled trial design without blinding. Participants were randomized into intervention group (n = 62) who were offered the Happy Parenting program delivered by educational psychologists and trainee educational psychologists, and a control group (n = 57) who were offered a parent talk after the intervention group had completed treatment. Parent participants were requested to complete questionnaires on their children’s behavior, their parenting stress, and discipline strategies. Results: Analysis was by intention-to-treat. The results indicated significant decrease in child problem behaviors, parenting stress and dysfunctional discipline strategies in the intervention group at post-intervention. Conclusion: This study provided promising evidence on the effectiveness of a parent education program, the Happy Parenting program, for Chinese preschool children with developmental disabilities. © 2016 Elsevier Ltd. All rights reserved.

What this paper adds This paper provided initial evidence for the effectiveness of a parent education program, the Happy Parenting Program, for parents with preschool children with developmental disabilities. The program was delivered in community settings as a universal program for all parents with preschool children with developmental disabilities. The promising evidence indicated the potential for the use of the program in early identification and intervention. 1. Introduction It is well established that parents with children with developmental disabilities experienced higher levels of distress than other parents. Children’s behavior problem, especially externalizing behavior, was a major stressor for parents (Hand,

∗ Corresponding author. E-mail address: [email protected] (C. Leung). http://dx.doi.org/10.1016/j.ridd.2016.05.015 0891-4222/© 2016 Elsevier Ltd. All rights reserved.

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Raghallaigh, Cuppage, Coyle, & Sharry, 2013; Woodman, Mawdsley, & Hauser-Cram, 2015). In a meta-analysis, Dyches, Smith, Korth, Roper, and Mandleco (2012) found a moderate association between positive parenting and child behavior among children with developmental disabilities. It was also found that change in positive parenting strategies could be the mediator between intervention and child behavior outcomes (Gardner, Burton, & Klimes, 2006). Schuiringa, van Nieuwenhuizen, de Castro, and Matthys (2015) found that parent-child relationship predicted both parenting behavior and child behavior problems. Parent response towards child behavior was influenced by parent-child relationship. The above suggests that interventions for families with children with developmental disabilities should support parents to enhance parent-child relationship and to increase positive parenting strategies. Studies on the effectiveness of parent training for parents with children with developmental disabilities indicated positive results. For example, in an earlier study using randomized controlled trial design, the Coping Skills Training Program was found to be effective in improving parents’ problem solving skills and communication skills, and decreasing parenting stress (Gammon & Rose, 1991). More recently, in a comparative treatment outcome study, the Parent Plus Program, a program originally designed for children with conduct disorder, was found to be effective in reducing child behavior problems (effect size = 0.49) and increasing parenting satisfaction in families with preschool children with developmental disabilities (Quinn, Carr, Carroll, & O’sullivan, 2007). The Stepping Stones Triple P was specifically developed for preschool children with developmental disabilities with behavior problems. Using randomized controlled trial design, it was found that the program was effective in reducing child behavior problems and parenting stress, and improving positive parenting style (Roberts, Mazzucchelli, Studman, & Sanders, 2006; Whittingham, Sofronoff, Sheffield, & Sanders, 2009). 1.1. The Hong Kong situation Services to preschool children with developmental disabilities are mainly provided through Early Education and Training Centers (EETCs), integrated program (IP) in kindergarten-cum-childcare-centres, and special childcare centres (SCCCs). Preschool children with developmental disabilities who are not receiving other preschool rehabilitation services can receive EETC services to facilitate their integration into mainstream education. IP places in kindergarten-cum-childcare-centres provide training and care to mildly disabled preschoolers to facilitate their integration into mainstream education. SCCCs provide training and care for moderately and severely disabled children (Social Welfare Department, 2015). To be eligible for these services, children should have been assessed by pediatricians or psychologists. According to Social Welfare Department (2014), in the year 2013-14, there were 2613 children enrolled in EETCs, 1860 children enrolled in IP places in kindergarten-cum-childcare-centres, and 1732 children enrolled in SCCCs. Two local studies found that parents of children with developmental disabilities reported higher stress than parents of children with typical development (Leung, Lau, Chan, Lau, & Chui, 2010; Leung & Tsang, 2010). In Hong Kong, there were some studies on the effectiveness of parent training programs for parents with preschool children with developmental disabilities, and they were based on programs developed overseas with validated Chinese versions. Level 4 Group Triple P program was found to be effective in decreasing child behavior problems, parenting stress and dysfunctional discipline strategies in families with preschool children with developmental disabilities (Leung, Fan, & Sanders, 2013). In a more recent study, the Parent-Child Interaction Therapy (PCIT) was found to be effective in reducing child behavior problems, parenting stress, inappropriate discipline practices, and in increasing positive parenting practices in families with primary or preschool children with Attention Deficit Hyperactivity Disorder (Leung, Tsang, Ng, & Choi, 2015b). These two programs were originally designed for children with conduct problems, rather than children with developmental disabilities, and the facilitators had to adapt the program to meet the needs of Chinese families with children with developmental disabilities, without compromising program fidelity. Though Stepping Stones Triple P was designed for children with developmental disabilities, there was no validated Chinese version in Hong Kong at the time of the study. 1.2. The Happy Parenting Program Triple P and PCIT were not specifically designed for children with developmental disabilities, and the inclusion criteria for PCIT included children’s behavior being in the clinical range. There was no existing validated Chinese version of Stepping Stones Triple P, and very few trials of Stepping Stones Triple P were effectiveness trials under normal service delivery conditions (Tellegen & Sanders, 2013). The Happy Parenting program was designed to specifically address the needs of families of children with developmental disabilities within a normal service delivery setting. Taking references from Triple P and PCIT, the Happy Parenting program was developed based on the social learning model, emphasizing modelling and rehearsal. The Happy Parenting program also took reference from a locally developed program, Hands-On Parent Empowerment20 (HOPE-20; Leung, Tsang, & Kwan, 2015) which was a universal program developed for Chinese parents with children aged two years old. These programs, together with other parenting training programs, focused on strategies to enhance adult responsiveness to children, behavioral strategies to train parents to act appropriately on their children’s behavior, and strategies to structure the environment to minimize undesirable behavior (Kong and Carta, 2013; Roberts et al., 2006). As mentioned earlier, parents of children with developmental disabilities experienced higher levels of distress than other parents and one of the stressors was their children’s behavior problems (Hand et al., 2013; Woodman et al., 2015). Parent-child relationship was also known to affect parenting behavior and child behavior problems (Schuiringa et al., 2015). The Happy Parenting program was designed to target these issues. To equip parents with the skills to manage child behavior, the Happy

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Table 1 Program Outline. Session

Objectives

Content

1.

Principles of positive parenting and relationship building

Building parent-child relationship: • Playing with children • Talking with children • Reflection of emotion Basic principles of applied behavior analysis:

2.

• Antecedent-Behavior-Consequence • Behavior diary • Reasons for misbehavior 3.

Promoting desirable behaviors

Encouraging positive behaviors: • Praise • Rewards • Behavior chart

4.

Teaching new behaviors: • Prompts and demonstration • Task analysis

5.

Reducing undesirable behaviors

Prevention of behavioral problems • • • •

Use of family rules Communication skills Giving effective instructions Recognizing and expressing emotions

Behavior management:

6.

• Ignoring • Preventing dangerous behavior • Use of consequences 7.

Behavior management: • Quiet time • Time-out

8.

Synthesis of skills and strategies

Skills integration and generalization to novel and “problematic” situations Course review and graduation ceremony

Parenting program included strategies to increase positive behavior and strategies to manage misbehavior. Furthermore, strategies to enhance parent-child relationship were introduced, together with strategies to teach new skills. The parenting strategies were explained with explicit reference to children with developmental disabilities and the parenting strategies were tailored taking into consideration the developmental level of the target children. For example, taking into consideration the limited cognitive and language (both expressive and receptive) abilities of the children, parents were suggested to use simple words when talking to children and to use demonstration to help children understand new learning tasks. Picture cards were introduced to help children express their emotions. Task analysis was introduced to help parents break down learning tasks into smaller steps. Examples specific to the Hong Kong situations were also included in the program, such as dining out in Chinese restaurants and use of time out procedures in the crowded living environment of Hong Kong. The details are in Table 1. Each session (except session 1) began with a review of the previous session and a discussion of the homework assignments. This was followed by mini-lecture/discussion on the new topics to be taught. Next, the homework was introduced and parents were encouraged to practice the homework activities with other parent participants using role play (modelling and rehearsal), with feedback from the facilitator. This was to ensure that parents could grasp the micro skills required for successful implementation of homework activities. A facilitator manual was produced together with powerpoint for presentation. Parents were provided with parent notes and a set of worksheets for homework. All facilitators were instructed to follow the facilitator’s manual.

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1.3. The present study The present study aimed to evaluate the efficacy of the Happy Parenting program for families with preschool children with developmental disabilities, using randomized controlled trial design. In addition, the mediator for change in child behavior problems would be explored. Based on the literature on parent training programs with children with developmental disabilities, it was hypothesized that: • Participants in the Happy Parenting program would report lower child behavior problems at post-intervention, compared with the control group. • Participants in the Happy Parenting program would report lower parenting stress at post-intervention, compared with the control group. • Participants in the Happy Parenting program would report less frequent use of dysfunctional discipline strategies at post-intervention, compared with the control group. • Change in parent discipline strategies was a mediator for change in child behavior problems in the Happy Parenting program. 2. Method 2.1. Design This study was a parallel randomized controlled trial without blinding, with allocation ratio of 1:1. The study was conducted in six EETCs of Heep Hong Society, a non-governmental organization in Hong Kong which provides professional rehabilitation services to clients with special needs. The six EETCs were chosen to cover the major districts of Hong Kong and for easy accessibility. 2.2. Participants The inclusion criteria were (i) children aged two to five years old; (ii) children diagnosed with developmental disabilities; and (iii) children attending rehabilitation services (EETC/IP/SCCC), or on the waiting list for rehabilitation services. Sample size calculation took reference from Hong Kong studies on parent training programs for children with developmental disabilities (Au et al., 2014; Leung et al., 2013) and the reported effect sizes were in the medium to large range. According to Cohen (1992), for a medium effect size, the sample size required was 64 per group, and for a large effect size, the sample size required was 26 per group. The final sample consisted of 119 participants. 2.3. Measures The measures consisted of a set of questionnaires on child behavior outcomes, parenting stress and dysfunctional discipline strategies to be completed by the participants before and after the intervention program. These outcome measures were chosen as child behavior problem was a major stressor for parents, and parent discipline strategies were related to child behavior. The primary outcome was child behavior problems and the secondary outcomes were parenting stress and parent discipline strategies. The intervention group participants were requested to complete the questionnaires again three months after completion of the program. Basic demographic information—participants were requested to provide information on target child’s age, gender, schooling, length of residence in Hong Kong, disability, parents’ age, employment, marital status, relationship between participant and child, family status, household income and social security status. Eyberg Child Behavior Inventory (ECBI; Eyberg & Ross, 1978)—this was a 36-item multidimensional measure of parental perception of disruptive behaviors in 2 to 16-year-old children. It consisted of two scales. The Intensity scale measured the frequency of disruptive behaviors on a 7-point scale. The Problem scale measured the number of disruptive behaviors that the parents were concerned about on a yes (1) no (0) basis. Higher scores indicated stronger degree of parental perceived behavioral problems of their children. The cut-off scores for the Intensity and Problem scales were 131 and 15 respectively (Colvin, Eyberg, & Adams, 1999). The Chinese version of the Inventory was validated by Leung, Chan, Pang, and Cheng (2003) for Hong Kong Chinese families. The reliabilities (Cronhach’s Alpha) were 0.94 and 0.93 for the Intensity scale and Problem scale, respectively. The original cut-off scores (131 and 15) were similar to the means of a group of children referred for behavior problems in the Chinese validation study, and thus, the original cut-off scores (131 and 15) were used in the present study. Parenting Stress Index/Short Form (PSI/SF; Abidin, 1990)—this was a 36-item questionnaire on parenting stress, measured on a 5-point scale. It consisted of three sub-scales, and a total could be calculated by adding up the scores of the three subscales. The three sub-scales were Parental Distress (PD), assessing the level of distress experienced by parents, Parent-Child Dysfunctional Interaction (PCDI), assessing parental perception of negative parent-child relationship; and Difficult Child (DC), measuring children’s problem behavior. The Chinese version of the PSI/SF has been validated by Lam (1999), and the reliability (Cronbach’s Alpha) of the 36 items was 0.89. There was no established cut-off score for Chinese population.

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Parenting Scale (PS; Arnold, O’Leary, Wolff, & Acker, 1993)—this was a 30-item scale measuring dysfunctional discipline strategies, with three sub-scales, Laxness, Overractivity and Verbosity. Parents rated their degree of agreement on a 7-point scale with one effective and one ineffective discipline strategy at either end. Higher scores indicated higher endorsement of ineffective parenting strategies. The internal consistency was 0.84. The Chinese version has been used in previous Hong Kong studies on the effectiveness of the Triple P program with Hong Kong Chinese parents (Leung, Sanders, Leung, Mak, & Lau, 2003, Leung et al., 2013), but there was no established cut-off scores for Chinese population. 2.4. Procedures The study was approved by the Human Subjects Ethics Sub-committee of The Hong Kong Polytechnic University. Information leaflets were distributed to the clients in the six EETCs of Heep Hong Society, and the information was also displayed on the Organization’s website to reach parents whose children were on the waiting list for rehabilitation services, or attending EETC/IP/SCCC programs in other organizations. Upon receiving participant consent, participants were randomized into the intervention group or control group within the EETC where they enrolled for the program. Randomization was performed by the third and fourth authors using a random number table. Intervention group parents participated in the 8-session Happy Parenting program and completed measures at three time-points, before commencement of the program (pre-intervention), after completion of the program (post-intervention), and three-months after program completion (follow-up). The control group participants were requested to complete the questionnaires twice, with an interval of about eight to 10 weeks. To encourage them to participate in the second assessment, they were invited to attend a talk on parenting by the second author. They were required to complete the questionnaires before the talk. 2.5. The intervention Intervention group participants attended the Happy Parenting program which consisted of eight weekly 2-hour group sessions. The intervention program was conducted by two educational psychologists (one of whom being the second author) and two trainee educational psychologists (the third and the fourth authors) under the supervision of the second author. The second author conducted one group and another educational psychologist conducted two groups. One of the trainee educational psychologists conducted one group and the other conducted two groups. Each session included mini lectures, group discussions, role play, and homework activities for parents to work with their children at home. The content included strategies to enhance parent-child relationship, strategies to teach new skills, and management of child behavior. Table 1 outlines the intervention. The control group was not offered any extra services during the period the intervention group attended the Happy Parenting program. The control group was offered a parent talk by the second author after the intervention group had completed the program. 2.6. Data analysis Independent t-tests and chi-squared tests were used to examine baseline difference between intervention and control groups. Independent t-test was used for comparison of continuous variables such as age of participants and pre-intervention scores. Chi-squared test was used for comparison of categorical variables such as gender of participants and family type. Analysis was by intention-to-treat. Missing data was estimated using SPSS multiple imputation with five imputations (Rubin, 1987). For the main analysis comparing the post-intervention results of the intervention and control groups, multiple regression was conducted to analyze the results. Multiple regression was used instead of analysis of covariance (ANCOVA) because pooled parameter estimates for multiple imputation data sets are available in multiple regression but no such pooled estimates are available for ANCOVA. The regression model and ANCOVA are basically the same regression model (Altman, 1991; Karabinus, 1983). The independent variables were group status and pre-intervention scores and the dependent variables were post-intervention scores. To estimate the magnitude of intervention effect, effect sizes (Cohen’s d) were calculated, with both adjusted and unadjusted estimates presented. The adjusted estimates were based on the pooled predicted post-intervention scores from multiple regression. To estimate whether the magnitude of change was statistically reliable, reliable change was calculated. It refers to a statistically reliable magnitude of change which is calculated as the difference between pre-intervention and post-intervention scores over standard error of difference (Jacobson & Truax, 1991). Logistic regression was used to examine the proportion of participants in the intervention and control groups who could achieve reliable change in the outcome measures (coded as a binary variable where 1: achieved; 0: did not achieve). To understand if the intervention group participants could maintain the program effect three months after completion of the program, repeated measures analysis of variance (ANOVA) with Bonferroni adjustment for multiple comparison was conducted to examine the change over the three time-points (pre-intervention, post-intervention, follow-up). It was

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Recruited into the study (N = 119) (6 Early Education and Training Centres)

Allocated to intervention group

Allocated to waitlist control group

(n = 62)

(n = 57)

Complete pre-intervention assessment

Complete pre-intervention assessment

(n = 62; 100%)

(n = 57; 100%)

Dropped out from program (n = 2, 3.2%)

Dropped out from study (n = 5; 8.8%)

Remained in program (n = 60; 96.8%)

Remained in study (n = 52; 91.2%)

Completed post-intervention assessment

Completed post-intervention assessment

(n = 62; 100%)

(n = 52; 91.2%)

Completed 3-month follow-up assessment (n = 52; 83.9%) Fig. 1. Flow of participants through each stage of the study.

assumed that participants could maintain their program gains if the post-intervention scores and the 3-month follow-up scores were significantly different from the pre-intervention scores. To examine the mediator for change in child behavior outcomes, Sobel test was used to test for the significance of the mediation effect. Change scores (difference between pre-intervention and post-intervention) for discipline strategies and child behavior problems were calculated. The independent variable was group status (intervention versus control group) and the dependent variable was change in child behavior problems. The mediators to be tested were the change in discipline strategy scores (PS-Laxness, PS-Overreactivity and PS-Verbosity). 3. Results 3.1. The sample Participants included 119 parents with children fulfilling the inclusion criteria. Among them, 62 were randomized into the intervention group and 57 into the control group. Among the target children, there were 56 (47.1%) with primary diagnosis as global developmental delay, 39 (32.8%) with primary diagnosis as Autism Spectrum Disorder, 12 (10.1%) with primary diagnosis as Attention Deficit Hyperactivity Disorder, and 12 (10.1%) with primary diagnosis as language delay. Two of the participants of the intervention group never turned up for any program sessions (pregnancy in one case and time clash in another case) and five participants of the control group dropped out from the study. For the postintervention assessment, 114 participants (62 participants from the intervention group and 52 from the control group) filled out post-intervention questionnaires. For the 3-month follow-up, 52 intervention group participants returned completed questionnaires. The flow of participants through the various stages is shown in Fig. 1. The demographic characteristics of the participants are shown in Table 2. There were no significant differences between the intervention and control groups in demographic characteristics and most pre-intervention measures, except PS-Laxness, with intervention group reporting higher scores than control group. The pre-intervention, post-intervention and follow-up

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Table 2 Demographic Characteristics of Participants. Intervention group(n = 62) Control group(n = 57) Significance

Gender of target child—boy Gender of target child—girl Target child born in Hong Kong Primary diagnosis of target child—global developmental delay Primary diagnosis of target child—Autism Spectrum Disorder Primary diagnosis of target child—Attention Deficit Hyperactivity Disorder Primary diagnosis of target child—language delay Education of target child—no schooling Education of target child—nursery class Education of target child—kindergarten Attending rehabilitation service in Heep Hong Society Attending rehabilitation service in other organizations On waiting list for rehabilitation service Relationship of participant to child—mother Relationship of participant to child—father Relationship of participant to child—stepmother Relationship of participant to child—others Participant married/de facto relationship Participant single/separated/divorced/widowed Family status—nuclear family Family status—extended family Family status—re-constituted family Family status—others Mother’s education—9 years or less Mother’s education—10 years or more Father’s education—9 years or less Father’s education—10 years or more Mother in employment Mother not in employment Father in employment Father not in employment Family income—HK$19,999 or below Family income—HK$20,000 or above Family on social welfare Family not on social welfare Age of target child Length of residence in Hong Kong of target child Age of mother Length of residence in Hong Kong of mother Age of father Length of residence in Hong Kong of father Number of children at home

Number (%)

Number (%)

48 (77.4%) 14 (22.6%) 61 (98.4%) 30 (48.4%) 18 (29.0%) 4 (6.5%) 10 (16.1%) 3 (4.8%) 6 (9.7%) 53 (85.5%) 47 (75.8%) 3 (4.8%) 12 (19.4%) 55 (88.7%) 4 (6.5%) 1 (1.6%) 2 (3.2%) 57 (91.9%) 5 (8.1%) 40 (64.5%) 19 (30.6%) 2 (3.2%) 1 (1.6%) 13 (21.7%) 47 (78.3%) 10 (16.9%) 49 (83.1%) 24 (40.0%) 36 (60.0%) 58 (98.3%) 1 (1.7%) 25 (41.0%) 36 (59.0%) 5 (8.2%) 56 (91.8%) Mean (SD) 4.06 (1.02) 3.69 (1.42) 36.28 (4.50) 23.71 (15.78) 40.58 (7.31) 35.90 (13.44) 1.48 (0.62)

45 (78.9%) 12 (21.1%) 53 (93.0%) 26 (45.6%) 21 (36.8%) 8 (14.0%) 2 (3.5%) 3 (5.3%) 7 (12.3%) 47 (82.5%) 44 (77.2%) 6 (10.5%) 7 (12.3%) 51 (89.5%) 5 (8.8%) 0 (0.0%) 1 (1.8%) 55 (96.5%) 2 (3.5%) 42 (75.0%) 12 (21.4%) 1 (1.8%) 1 (1.8%) 10 (17.5%) 47 (82.5%) 9 (16.1%) 47 (83.9%) 15 (26.3%) 42 (73.7%) 54 (98.2%) 1 (1.8%) 28 (50.0%) 28 (50.0%) 2 (3.5%) 55 (96.5%) Mean (SD) 4.28 (1.09) 3.88 (1.41) 36.71 (3.93) 22.18 (15.93) 40.43 (5.38) 34.32 (13.89) 1.54 (0.57)

X2 (1) = 0.04, p = 0.840 ␹2 (1) = 2.16, p = 0.142 ␹2 (3) = 6.99, p = 0.072

␹2 (2) = 0.23, p = 0.893

␹2 (2) = 2.21, p = 0.331

␹2 (3) = 1.39, p = 0.708

␹2 (1) = 1.11, p = 0.291 ␹2 (3) = 1.66, p = 0.645

␹2 (1) = 0.32, p = 0.575 ␹2 (1) = 0.02, p = 0.899 ␹2 (1) = 2.46, p = 0.117 ␹2 (1) = 0.00, p = 0.960 ␹2 (1) = 0.96, p = 0.328 ␹2 (1) = 1.16, p = 0.281

t(117) = 1.16, p = 0.250 t(117) = 0.74, p = 0.462 t(115) = 0.56, p = 0.580 t(115) = 0.52, p = 0.602 t(112) = 0.13, p = 0.897 t(111) = 0.61, p = 0.541 t(116) = 0.62, p = 0.535

(intervention group only) scores are shown in Table 3. All reliability estimates were above 0.70 except pre-intervention PS-Laxness and PS-Verbosity across the three time points. 3.2. Intention-to-treat analysis 3.2.1. Main analysis For child behavior, multiple regression results indicated that group status was a significant predictor for ECBI-Intensity (b = 7.43, t = 2.34, p = 0.019, adjusted d = 0.73, 95% CI [0.34, 1.09]) and ECBI-Problem (b = 2.90, t = 2.44, p = 0.015, adjusted d = 0.48, 95% CI [0.11, 0.84]), after controlling for pre-intervention scores. Intervention group participants reported lower ECBI-Intensity and ECBI-Problem scores than control group participants at post-intervention. For parenting stress, multiple regression results indicated that group status was a significant predictor for PSI total scores (b = 8.24, t = 3.29, p = 0.001, adjusted d = 0.44, 95% CI [0.07, 0.79]), after controlling for pre-intervention scores. Intervention group participants reported lower PSI total scores than control group participants at post-intervention. In terms of parent discipline strategies, multiple regression results indicated that group status was a significant predictor for PS-Laxness (b = 4.46, t = 3.27, p = 0.001, adjusted d = 0.54, 95% CI [0.16, 0.90]), PS-Overreactivity (b = 3.89, t = 3.00, p = 0.003, adjusted d = 0.98, 95% CI [0.59, 1.35]), and PS-Verbosity (b = 1.70, t = 1.98, p = 0.048, adjusted d = 0.68, 95% CI [0.30, 1.04]), after controlling for pre-intervention scores. Intervention group participants reported lower PS-Laxness, PS-Overreactivity and PS-Verbosity scores than control group participants at post-intervention.

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Table 3 Mean and Standard Deviation of Pre-intervention, Post-intervention and Follow-up Scores, Reliability and Unadjusted Effect Sizes.

Measures Pre-intervention ECBI-Intensity Post-intervention ECBI-Intensity Follow-up ECBI-Intensity Pre-intervention ECBI-Problem Post-intervention ECBI-Problem Follow-up ECBI-Problem Pre-intervention PSI-total Post-intervention PSI-total Follow-up PSI-total Pre-intervention PS-Laxness Post-intervention PS-Laxness Follow-up PS-Laxness Pre-intervention PS-Overreactivity Post-intervention PS-Overreactivity Follow-up PS-Overreactivity Pre-intervention PS-Verbosity Post-intervention PS-Verbosity Follow-up PS-Verbosity

Intervention group (n = 62)

Control group (n = 57)

Mean 127.15 122.34 121.58 13.82 10.16 10.60 109.93 101.61 101.66 41.32 35.15 35.46 32.77 29.29 30.19 29.63 27.50 27.21

Mean 131.09 132.21

SD 21.49 20.06

13.27 12.76

8.54 9.40

106.51 107.68

22.68 19.47

37.86 37.68

7.07 8.12

34.77 34.26

8.96 7.89

29.51 29.13

5.75 4.88

SD 21.86 22.38 20.87 7.65 6.75 6.81 16.34 17.26 16.18 8.42 8.64 8.61 9.33 9.20 9.00 4.16 5.31 5.29

Reliability

Significance (pre-intervention scores)

0.88 0.90 0.81 0.91 0.91 0.89 0.92 0.92 0.89 0.64 0.73 0.75 0.75 0.79 0.83 0.30 0.38 0.40

t(117) = 0.99, p =0.325

Unadjusted effect size [95% CI] (postintervention scores)

0.46 [0.09, 0.82] t(117) = 0.37, p =0.714 0.32 [−0.05, 0.68] t(117) = 0.95, p =0.345 0.33 [−0.04, 0.69] t(117) = 2.42, p =0.017 0.30 [−0.06, 0.66] t(117) = 1.19, p =0.237 0.58 [0.20, 0.94] t(117) = 0.13, p = 0.896 0.32 [−0.05, 0.68]

3.2.2. Reliable change Logistic regression was used to examine the differences in the intervention group and the control group in terms of proportion of participants achieving reliable change in outcome measures. The results were significant for PS-Laxness (OR = 0.18 p = 0.010) where a higher proportion of participants in the intervention group (25.8%, n = 16), were able to achieve reliable change, compared with the control group (5.3%, n = 3). The results were not significant for ECBI-Intensity (OR = 0.52, p = 0.264), ECBI-Problem (OR = 3.61 p = 0.380), PSI total scores (OR = 0.54, p = 0.235), PS-Overreactivity (OR = 0.42, p = 0.131) and PS-Verbosity (OR = 1.05, p = 0.920).

3.2.3. Follow-up results For follow-up results, only participants with complete pre- and post-intervention results were included as it was not meaningful to have both post-intervention and follow-up results estimated through multiple imputation. For ECBI-Intensity, the results were not significant, F(2, 122) = 2.23–2.52, p = 0.112–0.085, partial eta squared = 0.035 to 0.040. For ECBI-Problem, the results were significant, F(2, 122) = 9.23–10.09, p < 0.001, partial eta squared = 0.133 to 0.144. Post hoc comparison with Bonferroni adjustment indicated that the post-intervention and follow-up scores were significantly lower than the preintervention scores, indicating that participants could maintain their gains. For parenting stress, the results were significant, F(2, 122) = 14.27–15.74, p < 0.001, partial eta squared = 0.197 to 0.213. Post hoc comparison with Bonferroni adjustment indicated that the post-intervention and follow-up scores were significantly lower than the pre-intervention scores, indicating that participants could maintain their gains. In the case of PS-Laxness, the results were significant, F(2, 120) = 22.31–24.96, p < 0.001, partial eta squared = 0.271 to 0.294. For PS-Overreactivity, the results were significant, F(2, 122) = 5.67–6.50, p = 0.004–0.002, partial eta squared = 0.085 to 0.096. For PS-Verbosity, the results were significant, F(2, 122) = 6.38–8.34, p = 0.002–<0.001, partial eta squared = 0.095 to 0.120. For all PS sub-scales, post hoc comparison with Bonferroni adjustment indicated that the post-intervention and follow-up scores were significantly lower than the pre-intervention scores, indicating that participants could maintain their gains.

3.2.4. Mediator for change in child behavior The independent variable was group status and the dependent variables were changes in ECBI-Intensity and ECBIProblem. The mediator variables tested were changes in PS-Laxness, PS-Overreactivity and PS-Verbosity. Sobel test result indicated that change in PS-Laxness was a mediator for change in ECBI-Intensity, z = −2.48, p = 0.013. However, Sobel test result was not significant for change in PS-Overreactivity as a mediator for change in ECBI-Intensity, z = −1.27, p = 0.206. Sobel test results was not significant for change in PS-Verbosity as a mediator for change in ECBI-Intensity, z = −0.36, p = 0.720. Sobel test result was not significant for change in PS-Laxness as a mediator for change in ECBI-Problem, z = −1.19, p = 0.235, change in PS-Overreactivity as a mediator for change in ECBI-Problem, z = 0.06, p = 0.952, nor change in PS-Verbosity as a mediator for change in ECBI-Problem, z = 0.58, p = 0.562.

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3.3. Analysis based on participants with complete data For the main analysis, there were significant group effects for ECBI-Intensity, ECBI-Problem, PSI total scores, PS-Laxness, PS-Overreactivity, and PS-Verbosity. For achievement of reliable change, the results were again similar to that in the intention-to-treat analysis. For follow-up results, repeated measures ANOVA results were significant for ECBI-Intensity, ECBI-Problem, PSI total scores, PS-Laxness, PS-Overreactivity and PS-Verbosity. In all cases except ECBI-Intensity, the postintervention and the follow-up scores were significantly lower than the pre-intervention scores. For ECBI-Intensity, the follow-up scores were significantly lower than the pre-intervention scores. For mediation analysis, Sobel test result indicated that change in PS-Laxness was a mediator for change in ECBI-Intensity, z = −2.51, p = 0.012, but not change in ECBI-Problem. Sobel test results were not significant for change in PS-Overreactivity or change in PS-Verbosity as mediators for changes in ECBI-Intensity and ECBI-Problem.

4. Discussion Hypothesis 1 on reduction in child behavior was supported. Intervention group participants reported lower postintervention ECBI-Intensity and ECBI-Problem scores than control group participants. The effect sizes were in the medium range, and the results were comparable with the results of Leung et al. (2013) on Level 4 Group Triple P with Chinese families with preschool children with developmental disabilities, but smaller than those reported in Whittingham et al. (2009) and Roberts et al. (2006) for Stepping Stones Triple P. Hypothesis 2 on reduction in parenting stress was supported. Intervention group participants reported lower postintervention PSI total scores than control group participants, with medium effect sizes. The results were again comparable with the results of Leung et al. (2013) on Level 4 Group Triple P with Chinese families with preschool children with developmental disabilities. Hypothesis 3 on reduction of dysfunctional discipline strategies was also supported. Intervention group participants reported lower PS-Laxness, PS-Overreactivity, and PS-Verbosity scores than control group participants at post-intervention, with medium effect sizes. The results were consistent with Leung et al. (2013) but were smaller than that reported in Whittingham et al. (2009) for Stepping Stones Triple P. Hypothesis 4 was partially supported. Change in PS-Laxness was found to be a mediator for change in ECBI-Intensity. The results were consistent with Dyches et al. (2012) and Gardner et al. (2006) where change in parenting practice was found to be a mediator of program effect on child behavior outcome. The results suggested that the change in child behavior outcomes was due to a decrease in dysfunctional discipline strategies. This provided support for incorporating parenting strategies as the core component in parent training programs. The effect sizes in the present study were in the medium range, and were smaller than the large effect sizes reported in Stepping Stones Triple P. There was no significant difference in the achievement of reliable change between the intervention and control groups in child behavior and parenting stress. In the present study, the mean pre-intervention ECBI scores of the participants were below the clinical range, whereas they were above the clinical range in the Leung et al. (2013) and Whittingham et al. (2009) studies. This might be a possible reason for the medium effect size and the reliable change results. As child behavior problem was a significant stressor for parents and parenting behavior was associated with child behavior (Dyches et al., 2012; Hand et al., 2013; Woodman et al., 2015), the present study provided promising evidence that the Happy Parenting program could target the needs of families with preschool children with developmental disabilities. There was a reduction in child behavior problem, parenting stress, and dysfunctional discipline strategies after program participation. The results also indicated that change in discipline strategies (such as laxness) could act as a mediator for change in child behavior outcome. The present results, together with those of Gardner et al. (2006), provided support for the importance of targeting parenting practices in parent training programs. While our results could not provide direct evidence on the mechanism contributing to change in parenting stress, one possible explanation was that the acquisition and confidence in use of positive parenting strategies, as well as the decrease in child behavior problems, could potentially lead to a decrease in parenting stress. The Happy Parenting program is an attempt in the development of a parent training program for parents with children with developmental disabilities within a normal service delivery setting. Taking reference from local and overseas evidence-based parent training programs, strategies tailored to the needs of children with developmental disabilities were incorporated. The literature indicted that child behavior problem was a major stressor for parents of children with developmental disabilities and positive parenting strategies were negatively associated with child behavior problems (Dyches et al., 2012). The Happy Parenting program focused on equipping parents with positive parenting strategies (e.g., use of praise, rewards, logical consequences) which were known to be associated with decrease in child behavior problems. With a decrease in child behavior problems, it was expected that there could be a decrease in parenting stress. The Happy Parenting program was developed as a collaborative effort between educational psychologists in community service setting with frontline experience with children with developmental disabilities and educational/clinical psychologists from academic institutions with expertise in research and evaluation. This collaborative approach is consistent with the scientist-practitioner model in the practice of psychologists. This collaborative approach is also strategic for promoting evidence-based practice in the community setting.

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In the Happy Parenting program, there was no specific inclusion criterion about problem behavior level, and the program was made available to all families with children diagnosed with developmental disabilities. The program was delivered in normal service settings by frontline service staff, rather than university based clinics. This places the program within the context of a universal approach in the service for families with children with developmental disabilities, in line with a public health approach. Though the Happy Parenting program was first developed for Chinese families in Hong Kong, it could potentially be useful for other Chinese communities outside Hong Kong. It could also be used as a basis for similar programs in non-Chinese communities. 4.1. Limitations There were some limitations in the present study. First, the effect sizes were only in the medium range. More studies would be needed to further establish the evidence-base for the program. Second, only the intervention group participants were assessed for maintenance effect, as the control group was offered a parent talk after the intervention group had completed intervention. It was not possible to attribute the maintenance effect entirely to the program. Third, only parent reports were used as outcome measures. Future studies should try to employ other forms of measures such as observation of child behavior or parent-child interaction. Fourth, only the use of dysfunctional discipline strategies was measured. There was no measure of the use of positive parenting strategies or strategies to deal with misbehavior, or strategies to teach new skills. The measures used in the present study were measures validated for use with Hong Kong Chinese families, or measures that have already been used with Hong Kong Chinese families in previous research. Fifth, the reliability estimates of some of the PS sub-scales were low. Finally, there was no built-in fidelity check though all facilitators were instructed to follow the facilitator’s manual and to use the standard powerpoint slides provided. 4.2. Implications for research and practice Though the results of the present study were promising, more research would be needed to establish the evidencebase of the Happy Parenting program. Furthermore, the effectiveness of the program with different types of developmental disabilities would need to be examined. In the present study, the program was offered to parents of children who were receiving rehabilitation service or on the waiting list for rehabilitation services. Evidence on the effectiveness of the Happy Parenting program as a complementary program as part of existing rehabilitation service, or as an interim support for those waiting for service, would provide useful information on the most effective use of the program, to benefit those in need. The effectiveness of the program for Chinese communities outside Hong Kong should also be investigated. Future studies could also investigate the mechanisms underlying the change in child behavior and parenting stress in the context of parent training programs. The program is a brief, eight-session parent education program catering for children with developmental disabilities. It works on the core common factors bothering children and families with different forms of developmental disabilities. This short, sharp and evidence-based input to young children and families in need is strategic in early identification and intervention. The brief duration of the program could likely target the time barrier faced by parents of children with developmental disabilities, as they might have heavy time commitment in terms of caring for their children and attending various child specialist services. The brief duration and the specific focus on children with developmental disabilities could serve to enhance its acceptance and accessibility to parents of children with developmental disabilities. 5. Conclusions The Happy Parenting program was designed as a program for families with preschool children with developmental disabilities. The present study provided encouraging results on its effectiveness to indicate that the Happy Parent program was a promising program to target the needs of these families. Acknowledgement This project was supported by funding from Partnership Fund for the Disadvantaged. References Abidin, R. R. (1990). Parenting stress index/short form. Lutz, FL: Psychological Assessment Resources, Inc. Altman, D. G. (1991). Practical statistics for medical research. Washington, D.C: Chapman & Hall/CRC. Arnold, D. S., O’Leary, S. G., Wolff, L. S., & Acker, M. M. (1993). The parenting scale: a measure of dysfunctional parenting in discipline situations. 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