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A model for agreement between ratings on an ordinal scale
1188
Mathematical and Computer Modelling Reports representative of the effects of the environment for the population and a factor that represents the unique effect of each indivual in the cohort. We employ smoothing splines with the penalized likelihood methodology for estimation. We illustrate the methodology by applying it to data on leafhopper egg-laying rates. Key Wordsdeneralized
linear model, oviposition rate, Poisson, potato leafhopper
Riomerrirs Vol.44,pp. 397404,1988
A DISTRIBUTION-FREE
NEST SURVIVAL
MODEL
K. H. POLLOCKand W. L. CORNELIUS Department of Statistics, North Carolina State University, Box 8203, Raleigh, NC 2769543203, U.S.A. Abstraet-In many nest survival studies, nests are not found until after incubation has begun and nests that fail are of unknown age while nests that succeed can be aged afterwards. Typically ornithologists have considered the survival time to be from first encounter and have used the Mayfield method (Mayfield, 1961, Wilson Bulletin 73, 255-261; Mayfield, 1975, Wilson Bulletin 87, 45&466) or variations of it. Here we consider a new discrete survival model that allows estimation of the survival distribution from the time of nest initiation. Nests that succeed are used to estimate the proportions of nests being found (encountered) in each time interval. Assuming that these encounter probabilities also apply to the nests that fail, it is possible to estimate a series of discrete failure time probabilities for all the nests. We present maximum likelihood estimators and computer programs to calculate them. Our methodology is illustrated and compared to other approaches using real data on mourning dove nests. Key Words-Distribution-free
procedure, Mayfield model, nest survival model, survival analyses
Biomerrics, Vol.44,pp. 539-548,1988
A MODEL
FOR AGREEMENT BETWEEN AN ORDINAL SCALE
RATINGS
ON
ALANAGRESTI Department of Statistics, University of Florida, Gainesville, FL 32611, U.S.A. Abstract-A
class of models is proposed for describing agreement between raters who classify a sample on a subjective ordinal scale. The class is obtained by adding to the independence model a component describing baseline association between ratings and a main-diagonal component representing additional incidence of exact agreement. Special cases include the quasi-uniform association model introduced by Goodman (1979, Journal of the American Statistical Association 74, 537-552) and a diagonal-parameter model for nominal-scale agreement proposed by Tanner and Young (1985, Journal of the American Statistical Association 80, 175-180). The model having the structure of uniform association plus a main-diagonal parameter is used to describe agreement between pathologists evaluating carcinoma in situ of the uterine cervix and between neurologists diagnosing multiple sclerosis. The models presented are log-linear and can be fitted using SAS and GLIM. Key Wordr-Category distinguishability, dependent samples, kappa, log-linear models, quasi-independence, quasi-symmetry, uniform association
Mathematical and Computer Modelling Reports representative of the effects of the environment for the population and a factor that represents the unique effect of each indivual in the cohort. We employ smoothing splines with the penalized likelihood methodology for estimation. We illustrate the methodology by applying it to data on leafhopper egg-laying rates. Key Wordsdeneralized
linear model, oviposition rate, Poisson, potato leafhopper
Riomerrirs Vol.44,pp. 397404,1988
A DISTRIBUTION-FREE
NEST SURVIVAL
MODEL
K. H. POLLOCKand W. L. CORNELIUS Department of Statistics, North Carolina State University, Box 8203, Raleigh, NC 2769543203, U.S.A. Abstraet-In many nest survival studies, nests are not found until after incubation has begun and nests that fail are of unknown age while nests that succeed can be aged afterwards. Typically ornithologists have considered the survival time to be from first encounter and have used the Mayfield method (Mayfield, 1961, Wilson Bulletin 73, 255-261; Mayfield, 1975, Wilson Bulletin 87, 45&466) or variations of it. Here we consider a new discrete survival model that allows estimation of the survival distribution from the time of nest initiation. Nests that succeed are used to estimate the proportions of nests being found (encountered) in each time interval. Assuming that these encounter probabilities also apply to the nests that fail, it is possible to estimate a series of discrete failure time probabilities for all the nests. We present maximum likelihood estimators and computer programs to calculate them. Our methodology is illustrated and compared to other approaches using real data on mourning dove nests. Key Words-Distribution-free
procedure, Mayfield model, nest survival model, survival analyses
Biomerrics, Vol.44,pp. 539-548,1988
A MODEL
FOR AGREEMENT BETWEEN AN ORDINAL SCALE
RATINGS
ON
ALANAGRESTI Department of Statistics, University of Florida, Gainesville, FL 32611, U.S.A. Abstract-A
class of models is proposed for describing agreement between raters who classify a sample on a subjective ordinal scale. The class is obtained by adding to the independence model a component describing baseline association between ratings and a main-diagonal component representing additional incidence of exact agreement. Special cases include the quasi-uniform association model introduced by Goodman (1979, Journal of the American Statistical Association 74, 537-552) and a diagonal-parameter model for nominal-scale agreement proposed by Tanner and Young (1985, Journal of the American Statistical Association 80, 175-180). The model having the structure of uniform association plus a main-diagonal parameter is used to describe agreement between pathologists evaluating carcinoma in situ of the uterine cervix and between neurologists diagnosing multiple sclerosis. The models presented are log-linear and can be fitted using SAS and GLIM. Key Wordr-Category distinguishability, dependent samples, kappa, log-linear models, quasi-independence, quasi-symmetry, uniform association