Linda Collins

Linda Collins
Linda Collins
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Professor of Social and Behavioral Sciences

Professional overview

Linda M. Collins is Professor of Global Public Health in the Department of Social and Behavioral Sciences, with a secondary appointment in the Department of Biostatistics. She earned her B.A. in Psychology at the University of Connecticut and her Ph.D. in Quantitative Psychology at the University of Southern California.

Collins’ research interests are focused on the development, dissemination, and application of the multiphase optimization strategy (MOST), a framework for the optimization of behavioral, biobehavioral, and social-structural interventions. The objective of MOST is to improve intervention effectiveness, efficiency, economy, and scalability. She is currently collaborating on research applying MOST in the areas of smoking cessation, the prevention of excessive drinking and risky sex in college students, and HIV services.

Collins’ research has been funded by the National Institute on Drug Abuse, the National Institute on Alcohol Abuse and Alcoholism, and the National Science Foundation, among others. She has given more than 150 presentations on MOST around the world, and her publications have appeared in journals in the fields of behavioral science, quantitative methodology, medicine, and engineering.

Collins has held tenured faculty positions at the University of Southern California and at Penn State University, where she was Distinguished Professor of Human Development and Family Studies and Director of The Methodology Center. She is a Fellow of the American Psychological Association, the Association for Psychological Science, the Society of Behavioral Medicine, and is a past president of the Society of Multivariate Experimental Psychology and the Society for Prevention Research.

Education

BA, Psychology, University of Connecticut, Storrs, CT
PhD, Quantitative Psychology, University of Southern California, Los Angeles, CA

Honors and awards

Fulbright Specialist, National University of Ireland Galway (2018)
Pauline Schmitt Russell Distinguished Career Award, Pennsylvania State University’s College of Health and Human Development (2017)
Evan G. and Helen G. Pattishall Outstanding Research Achievement Award, Pennsylvania State University’s College of Health and Human Development (2011)
President’s Award, Society for Prevention Research (2004)
Faculty Scholar Medal for the Social and Behavioral Sciences, Pennsylvania State University (2000)
Psychology Department Teacher of the Year, University of Southern California (1992)
Psychology Department Mentorship Award, University of Southern California (1991)
Society of Multivariate Experimental Psychology Award for Distinguished Early Career Contributions to Multivariate Behavioral Research (1991)

Areas of research and study

Behavioral Science
Cost Effectiveness
Cost-effective Health Programs and Policies
Dissemination and Implementation of Evidence-based Programs

Publications

Publications

Latent transition analysis and how it can address prevention research questions

Collins, L. M., Graham, J. W., Rousculp, S. S., Fidler, P. L., Pan, J., & Hansen, W. B. (n.d.).

Publication year

1994

Journal title

NIDA Research Monograph Series

Issue

142

Page(s)

81-111
Abstract
Abstract
The objective of this chapter is to introduce latent transition analysis (LTA) to the substance use prevention research community. LTA is a new methodological technique for testing stage-sequential models, such as models of substance use onset. LTA estimates several different sets of parameters. One of these sets is the transition probability matrix, which contains information about the probability of movement between stages in the model. LTA can be used to evaluate the effectiveness of prevention intervention programs by comparing the transition probability matrices of the program and control groups. If the prevention program is successful, the transition probability matrices will indicate that the probability of moving to a more advanced stage of drug use is lower for the program participants than for the control group. An advantage of taking a stage-sequential approach is that examining the transition probability matrix reveals how effective a program is for individuals entering the program with different levels and types of substance use experience.

New statistical methods for substance use prevention research

Collins, L. M., & Seitz, L. A. (n.d.).

Publication year

1994

Journal title

NIDA Research Monograph Series

Issue

142

Page(s)

1-12

Seven ways to increase power without increasing N

Hansen, W. B., & Collins, L. M. (n.d.).

Publication year

1994

Journal title

NIDA Research Monograph Series

Issue

142

Page(s)

184-195
Abstract
Abstract
Many readers of this monograph may wonder why a chapter on statistical power was included. After all, by now the issue of statistical power is in many respects mundane. Everyone knows that statistical power is a central research consideration, and certainly most National Institute on Drug Abuse grantees or prospective grantees understand the importance of including a power analysis in research proposals.

Some design, measurement, and analysis pitfalls in drug abuse prevention research and how to avoid them: Let your model be your guide

Collins, L. M. (n.d.).

Publication year

1994

Journal title

NIDA Research Monograph Series

Issue

139

Page(s)

95-114

Goodness-of-Fit Testing for Latent Class Models

Collins, L. M., Fidler, P. L., Wugalter, S. E., & Long, J. D. (n.d.).

Publication year

1993

Journal title

Multivariate Behavioral Research

Volume

28

Issue

3

Page(s)

375-389
Abstract
Abstract
Latent class models with sparse contingency tables can present problems for model comparison and selection, because under these conditions the distributions of goodness-of-fit indices are often unknown. This causes inaccuracies both in hypothesis testing and in model comparisons based on normed indices. In order to assess the extent of this problem, we carried out a simulation investigating the distributions of the likelihood ratio statistic G2, the Pearson statistic X2, and a new goodness-of-fit index suggested by Read and Cressie (1988). There were substantial deviations between the expectation of the chi-squared distribution and the means of the G2 and Read and Cressie distributions. In general, the mean of the distribution of a statistic was closer to the expectation of the chi-squared distribution when the average cell expectation was large, there were fewer indicator items, and the latent class measurement parameters were less extreme. It was found that the mean of the X2 distribution is generally closer to the expectation of the chi-squared distribution than are the means of the other two indices we examined, but the standard deviation of the X2 distribution is considerably larger than that of the other two indices and larger than the standard deviation of the chi-squared distribution. We argue that a possible solution is to forgo reliance on theoretical distributions for expectations and quantiles of goodness-of-fit statistics. Instead, Monte Carlo sampling (Noreen, 1989) can be used to arrive at an empirical central or noncentral distribution.

Latent Class Models for Stage-Sequential Dynamic Latent Variables

Collins, L. M., & Wugalter, S. E. (n.d.).

Publication year

1992

Journal title

Multivariate Behavioral Research

Volume

27

Issue

1

Page(s)

131-157
Abstract
Abstract
Stage-sequential dynamic latent variables are of interest in many longitudinal studies. Measurement theory for these latent variables, called Latent Transition Analysis (LTA), can be found in recent generalizations of latent class theory. LTA expands the latent Markov model to allow applications to more complex latent variables and the use of multiple indicators. Because complex latent class models result in sparse contingency tables, that may lead to poor parameter estimation, a simulation study was conducted in order to determine whether model parameters are recovered adequately by LTA, and whether additional indicators result in better measurement or in impossibly sparse tables. The results indicated that parameter recovery was satisfactory overall, although as expected the standard errors were large in some conditions with few subjects. The simulation also indicated that at least within the conditions examined here, the benefits of adding indicators outweigh the costs. Additional indicators improved standard errors, even in conditions producing extremely sparse tables. An example of LTA analysis of empirical data on math skill development is presented.

Modeling Transitions in Latent Stage-Sequential Processes: A Substance Use Prevention Example

Graham, J. W., Collins, L. M., Wugalter, S. E., Chung, N. K., & Hansen, W. B. (n.d.).

Publication year

1991

Journal title

Journal of consulting and clinical psychology

Volume

59

Issue

1

Page(s)

48-57
Abstract
Abstract
This article illustrates the use of latent transition analysis (LTA), a methodology for testing stage-sequential models of individual growth. LTA is an outgrowth of latent class theory and is a particular type of latent Markov model emphasizing the use of multiple manifest indicators. LTA is used to compare the fit of two models of early adolescent substance use onset and to assess the effects of a school-based substance use prevention program on Ss measured in 7th grade and again in 8th grade. Several interesting findings emerged. First, a model of substance use onset including both alcohol and tobacco use as possible starting points fit better than a model that included alcohol use as the only starting point. Second, Ss who had tried tobacco but not alcohol in 7th grade seemed to be on an accelerated onset trajectory. Third, the normative education prevention program was generally successful, except for the students who had tried only tobacco in 7th grade.

The measurement of dynamic latent variables in longitudinal aging research: Quantifying adult development

Collins, L. M. (n.d.).

Publication year

1991

Journal title

Experimental Aging Research

Volume

17

Issue

1

Page(s)

13-20
Abstract
Abstract
Dynamic latent variables involve systematic intraindividual change over time. Although it seems natural to apply traditional measurement theory to dynamic latent variables, in fact this is often inappropriate. Traditional measurement theory is based on the idea of static latent variables and offers little guidance to the researcher who wishes to measure a dynamic latent variable with a high degree of accuracy and validity. It is the contention of this article that measurement of a dynamic latent variable must start from a clearly defined substantive theory about human development. Two approaches that take this perspective are presented: the longitudinal Guttman simplex (LGS), a measurement model for dynamic latent variables undergoing irreversible cumulative, unitary development; and latent transition analysis (LTA), a more general latent class measurement model.

A note on the unbiased estimation of the intraclass correlation

Donoghue, J. R., & Collins, L. M. (n.d.).

Publication year

1990

Journal title

Psychometrika

Volume

55

Issue

1

Page(s)

159-164
Abstract
Abstract
The intraclass correlation, ρ, is a parameter featured in much psychological research. Two commonly used estimators of ρ, the maximum likelihood and least squares estimators, are known to be negatively biased. Olkin and Pratt (1958) derived the minimum variance unbiased estimator of the intraclass correlation, but use of this estimator has apparently been impeded by the lack of a closed form solution. This note briefly reviews the unbiased estimator and gives a FORTRAN 77 subroutine to calculate it.

The Measurement of Dynamic Latent Variables in Longitudinal Aging Research: Quantifying Adult Development

Collins, L. M. (n.d.).

Publication year

1990

Journal title

Gerodontology

Volume

9

Issue

4

Page(s)

127-134
Abstract
Abstract
Dynamic latent variables involve systematic intraindividual change over time. Although it seems natural to apply traditional measurement theory to dynamic latent variables, in fact this is often inappropriate. Traditional measurement theory is based on the idea of static latent variables and offers little guidance to the researcher who wishes to measure a dynamic latent variable with a high degree of accuracy and validity. It is the contention of this article that measurement of a dynamic latent variable must start from a clearly defined substantive theory about human development. Two approaches that take this perspective are presented; the longitudinal Guttman simplex (LGS), a measurement model for dynamic latent variables undergoing irreversible cumulative, unitary development; and latent transition analysis (LTA), a more general latent class measurement model.

Using the longitudinal guttman simplex as a basis for measuring growth

Collins, L. M., & Cliff, N. (n.d.).

Publication year

1990

Journal title

Psychological bulletin

Volume

108

Issue

1

Page(s)

128-134
Abstract
Abstract
Many difficulties inherent in the measurement of growth stem from the use of traditional measurement methodologies. The longitudinal Guttman simplex (LGS), an alternative approach based on a model of growth, is discussed in this article. The LGS has several advantages over traditional methodology. First, interindividual differences in developmental rates are a part of the model. Second, the LGS procedure can easily handle any number of occasions of measurement. Third, the LGS is suited to nonlinear as well as linear monotonic growth. Fourth, a consistency index associated with the LGS methodology, CL, indicates the extent to which cumulative, unitary development characterizes a particular latent variable. Finally, and perhaps most important, because a model of the growth undergone by the latent variable being measured is incorporated in the LGS model the resulting instruments enjoy a high level of construct validity. The LGS is limited to cumulative, unitary development; additional measurement theories are needed for other kinds of development.

An Ordinal I Scaling Method for Questionnaire and Other Ordinal I Data

Cliff, N., Collins, L. M., Zatkin, J., Gallipeau, D., & McCormick, D. J. (n.d.).

Publication year

1988

Journal title

Applied Psychological Measurement

Volume

12

Issue

1

Page(s)

83-97
Abstract
Abstract
This paper reports the development and application of a method for ordering persons and items (or stim uli) when responses are ordinal. The method applies most directly to data where responses are dichoto mous, indicating agreement or acceptableness or simi larity, and can be assumed to reflect proximity rather than dominance. It orders rows and columns of the re sponse matrix into “parallelogram” form, using pair- wise interchange procedures, followed by other steps. The method was applied to several sets of question naire data and one set of archeological data, with rea sonable success. Other applications and extensions are suggested. Index terms: Dichotomous responses, Interchange methods, Ordinal scaling, Parallelogram scaling, Proximity data, Questionnaire responses.

Omega: A General Formulation of the Rand Index of Cluster Recovery Suitable for Non-disjoint Solutions

Collins, L. M., & Dent, C. W. (n.d.).

Publication year

1988

Journal title

Multivariate Behavioral Research

Volume

23

Issue

2

Page(s)

231-242
Abstract
Abstract
Cluster recovery indices are more important than ever, because of the necessity for comparing the large number of clustering procedures available today. Of the cluster recovery indices prominent in contemporary literature, the Hubert and Arabie (1985) adjustment to the Rand index (1971) has been demonstrated to have the most desirable properties (Milligan & Cooper, 1986). However, use of the Hubert and Arabie adjustment to the Rand index is limited to cluster solutions involving non-overlapping, or disjoint, clusters. The present paper introduces a generalization of the Hubert and Arabie adjusted Rand index. This generalization, called the Omega index, can be applied to situations where both, one, or neither of the solutions being compared is non-disjoint. In the special case where both solutions are disjoint, the Omega index is equivalent to the Hubert and Arabie adjusted Rand index.

The Longitudinal Guttman Simplex: A New Methodology for Measurement of Dynamic Constructs in Longitudinal Panel Studies

Collins, L. M., Cliff, N., & Dent, C. W. (n.d.).

Publication year

1988

Journal title

Applied Psychological Measurement

Volume

12

Issue

3

Page(s)

217-230
Abstract
Abstract
Traditional psychometric procedures can be inade quate for the measurement of dynamic constructs in longitudinal panel studies. This paper introduces an al ternative based on the longitudinal Guttman simplex (LGS) model, a measurement model developed espe cially for dynamic constructs measured longitudinally. The LGS is a model of cumulative, unitary develop ment. It is cumulative in the sense that as persons ac quire new skills (or abilities, or opinions), earlier ob tained skills are retained; it is unitary in the sense that all persons progress through a sequence of skills in the same skill order. CL, a consistency index that gives the researcher a measure of the extent to which the LGS model axioms are obeyed in a given dataset, is introduced. By making use of this consistency index, the researcher can develop scales uniquely sensitive to cumulative, unitary development. LGSCLUS, an explor atory procedure to find longitudinal Guttman scales in empirical datasets, is described. An artificial data study is reported, the purpose of which was to test the performance of LGSCLUS under controlled conditions. The artificial data study showed that, in general, LGSCLUS recovers longitudinal Guttman scales with a high degree of accuracy. There remains a need for measurement procedures for dynamic constructs exhib iting types of development other than cumulative and unitary. Index terms: Dynamic constructs, Gutt man simplex, Longitudinal panel studies, Mathemati cal models, Measurement theory, Scaling, Three-set data.

Frequency and adequacy of breast cancer screening among elderly hispanic women

Richardson, J. L., Marks, G., Solis, J. M., Collins, L. M., Birba, L., & Hisserich, J. C. (n.d.).

Publication year

1987

Journal title

Preventive Medicine

Volume

16

Issue

6

Page(s)

761-774
Abstract
Abstract
Studies have demonstrated that Hispanic (relative to Anglo) women are at greater risk for late-stage breast cancer diagnosis. Screening irregularity may be a factor contributing to late-stage diagnosis, yet virtually nothing is known about the breast cancer-screening behavior of Hispanic women. We interviewed 600 elderly Hispanic women residing in Los Angeles to collect information on frequency of physician breast examinations and mammography and on regularity and competence of breast self-examination. Predictors of screening were also examined. Fifty percent of our sample indicated that they had had a breast exam within the past year; 12.5% had had a mammogram within the past year (74% never had had a mammogram); and 47% reported that they had performed breast self-examination within the past month. Few of the women were able to demonstrate adequate breast self-examination technique on a foam breast model, and only 1% found all five lumps present. Thus, although the observed frequency of screening and self-examination is comparable to national norms, it is unlikely that our subjects' attempts at self-examination would lead to early breast cancer detection. Age, educational level, emotional reactions to screening, and media cues predicted screening behavior. Physician instruction in breast self-examination increased the frequency and adequacy of self-examination. Perceived susceptiblity to cancer, perceived benefits of early detection, and level of acculturation were not strong predictors. The extent to which our results generalize to other subpopulations of Hispanic women is discussed.

Health behavior of elderly Hispanic women: Does cultural assimilation make a difference?

Marks, G., Solis, J., Richardson, J. L., Collins, L. M., Birba, L., & Hisserich, J. C. (n.d.).

Publication year

1987

Journal title

American journal of public health

Volume

77

Issue

10

Page(s)

1315-1319
Abstract
Abstract
The role of cultural assimilation in Hispanic health behavior has received little empirical examination. Prior studies have operationalized assimilation primarily in terms of language preference and have obtained weak or no effects. We interviewed 603 elderly Hispanic women residing in Los Angeles to evaluate the usefulness of cultural factors as predictors of preventive health behavior (e.g., physical examination, screening for breast cancer) more rigorously. Factor analysis of responses yielded four dimensions of cultural assimilation: 'language preference', 'country of birth', 'contact with homeland', and 'attitudes about children's friends'. After controlling for education and age, no dimension of assimilation associated strongly or consistently with health behavior. Of the four dimensions, use of English language associated most closely with increased screening, although most of the effects for language were small in magnitude. These findings, coupled with those of other studies, strongly suggest that cultural factors may have little impact on the health behavior of Hispanics. Access to and availability of services, affective reactions toward screening, and sociodemographic factors are stronger determinants of Hispanic health practices.

Implementation effectiveness trial of a social influences smoking prevention program using schools and television

Flay, B. R., Hansen, W. B., Johnson, C. A., Collins, L. M., Dent, C. W., Dwyer, K. M., Grossman, L., Hockstein, G., Rauch, J., Sobel, J. L., Sobol, D. F., Sussman, S., & Ulene, A. (n.d.).

Publication year

1987

Journal title

Health Education Research

Volume

2

Issue

4

Page(s)

385-400
Abstract
Abstract
Results are reported from a quasi-experimental implementation effectiveness trial of a television and school-based smoking prevention program. The program used the social influences approach, focusing on peer, family and media influences on adolescents to become smokers, and providing grade 7 students (age 12-13) with the knowledge and skills to resist them. The evaluation allowed for assessments of: the value of coordinated television programming in increasing school, student and parent availability and acceptance of the program; the effects of program context (whether all or half of a grade cohort received the program in school) on participation and subsequent smoking behavior; and the effects of parental participation in prevention activities on subsequent student smoking. Data on availability, acceptance, participation and implementation are reported and immediate post-test and 1- and 2-year follow-up results. Strong effects of television programming and context on availability, acceptance and participation were found. Significant associations were also found between each television viewing and parental involvement and subsequent student smoking, but a lack of overall program effects on smoking outcomes limit their interpretation. Constraints on programming and research design suggest: (i) possible limitations to program effects we might reasonably expect in real-world applications of the social influences approach and (ii) the need for future true experimental efficacy trials to determine exactly what level of programming will be needed to achieve significant real-world effects.

Psychosocial Predictors of Young Adolescent Cigarette Smoking: A Sixteen‐Month, Three‐Wave Longitudinal Study

Collins, L. M., Sussman, S., Rauch, J. M., Dent, C. W., Johnson, C. A., Hansen, W. B., & Flay, B. R. (n.d.).

Publication year

1987

Journal title

Journal of Applied Social Psychology

Volume

17

Issue

6

Page(s)

554-573
Abstract
Abstract
Understanding the psychosocial factors that predict cigarette smoking onset in young people is of crucial importance for prevention efforts. The present study examined prospective psychosocial predictors of smoking in a three‐wave longitudinal data set. Similar in design to an earlier study by Chassin, Presson, Sherman, Corty, and Olshavsky (1984), the present study replicated their work, and extended it by (a) using composite predictors derived from exploratory factor analysis, (b) including prior behavior as a predictor, (c) using a design extended over three waves of data collection, and (d) using a sample composed primarily of urban teenagers. Subjects were 3295 7th‐grade students at the beginning of the study. The subjects completed a questionnaire containing items tapping cigarette smoking behavior and psychosocial items that have previously been shown to predict smoking behavior. Forty‐one psychosocial items on the Wave 1 (initial) questionnaire were factor analyzed, and five factors were retained. Subscale scores were constructed based on these factors and were used as predictors. Regression analyses were performed using the subscales and pretest smoking frequency to predict a continuous measure of smoking, and discriminant analyses were performed to predict transitions between qualitative levels of smoking. Prior smoking behavior was the most important predictor of future smoking. Four of the subscales, Social Disapproval, Risk Taking/Rebelliousness, Perceived Smoking Prevalence, and Motivation to Comply, were significant predictors. One subscale, Physical Consequences from Smoking, was not predictive of smoking in any of the analyses. The effect sizes cross‐validated well. It is suggested that an integrative model of smoking initiation developed by Flay, d'Avernas, Best, Kersell, and Ryan (1983) best summarizes the results of the present study.

BINCLUS: Nonhierarchical Clustering of Binary Data

Cliff, N., McCormick, D. J., Zatkin, J. L., Cudeck, R. A., & Collins, L. M. (n.d.).

Publication year

1986

Journal title

Multivariate Behavioral Research

Volume

21

Issue

2

Page(s)

201-227
Abstract
Abstract
BINCLUS is a clustering procedure designed for aggregating binary variables into relatively homogenous clusters. It uses any of several indices of binary association and operates by a variation on the “average linkage⃍ principle. It was tried out on a number of sets of artificial data and found to be extremely successful. With real data, where clusters are typically less clearly defined, two modifications were useful in clarifying the results. Results of using BINCLUS with two sets of real data are given.

Factor Recovery in Binary Data Sets: A Simulation

Collins, L. M., Cliff, N., McCormick, D. J., & Zatkin, J. L. (n.d.).

Publication year

1986

Journal title

Multivariate Behavioral Research

Volume

21

Issue

3

Page(s)

377-391
Abstract
Abstract
The present study compares the performance of phi coefficients and tetrachorics ailong two dimensions of factor recovery in binary data. These dimensions are (a) accuracy of nontrivial factor identification, and (b) factor structure recovery given a priori knowledge of the correct number of factors to rotate. Nontrivial factor identification was poor for both indices, with phi's performing slightly better than tetrachorics. In contrast, factor structure recovery was quite good when the correct number of factors was rotated. Phi coefficients generally yielded better factor structure recovery than tetrachorics and were better at preventing items from intruding onto factors where they did not belong, while tetrachorics were better than phi's at preventing items from being omitted from factors where they should have been included. The solutions based on tetrachorics contained many Hey wood cases. It is suggested that for most applications it is preferable to base factor analysis on phi coefficients.

High-school smoking prevention: Results of a three-year longitudinal study

Anderson Johnson, C., Hansen, W. B., Collins, L. M., & Graham, J. W. (n.d.).

Publication year

1986

Journal title

Journal of Behavioral Medicine

Volume

9

Issue

5

Page(s)

439-452
Abstract
Abstract
This study compared two strategies for preventing cigarette smoking among high-school students. One strategy emphasized social-pressure resistance skills, while the other focused on education about health concerns which are relevant to high-school students. Additionally, the use of same-age peer leaders and the use of familiar models in media presentations were investigated. The results suggest that social-influences resistance training was efficacious in reducing transitions to higher use by those who had previously experimented with cigarettes. Health education was most effective in preventing initial experimentation among those who had not smoked prior to the beginning of the study. Neither program was effective in limiting transitions among those who had gone beyond the experimental stage of smoking, and neither had any effect on encouraging cessation. There were no differences which could be attributed to peer leaders or to familiar media models. During later adolescence, a combined health education and social skills training approach is advocated. It is suggested that while there are some gains by implementing programs during late adolescence, prevention programs targeted at younger students may be more effective generally.

Agreement Between Retrospective Accounts of Substance Use and Earlier Reported Substance Use

Collins, L. M., Graham, J. W., Hansen, W. B., & Johnson, C. A. (n.d.).

Publication year

1985

Journal title

Applied Psychological Measurement

Volume

9

Issue

3

Page(s)

301-309
Abstract
Abstract
This present study examined agreement between retrospective accounts of substance use and earlier re ported substance use in a high school age sample. Three issues were addressed: (1) extent of overall agreement; (2) evidence for the presence of a response-shift bias; and (3) extent to which current use biases recall of substance use. Subjects were 415 high school students who took part in a smoking prevention program. At the last measurement, which took place 2½ years after the pretest, the students were asked to recall pretest use of tobacco, alcohol, and marijuana, and use one year earlier. Results showed an overall tendency for students to recall less use of uncontrolled substances than had been previously reported. For the one controlled substance included in the questionnaire, marijuana, current nonusers tended to recall less use than they had reported at the time, whereas current users tended to recall more use than had been re ported. The present study found no evidence for a response-shift bias. It is suggested that the explicitly worded anchors on the response scales helped prevent such a bias. Finally, the results suggest that current use biases recall of past use to a substantial extent, and that this bias affects recall of alcohol use most se verely.

Attrition in prevention research

Hansen, W. B., Collins, L. M., Malotte, C. K., Johnson, C. A., & Fielding, J. E. (n.d.).

Publication year

1985

Journal title

Journal of Behavioral Medicine

Volume

8

Issue

3

Page(s)

261-275
Abstract
Abstract
Selective attrition can detract from the internal and external validity of longitudinal research. Four tests of selective attrition applicable to longitudinal prevention research were conducted on data bases from two recent studies. These tests assessed (1) differences between dropouts and stayers in terms of pretest indices of primary outcome variables (substance use), (2) differences in change scores for dropouts and stayers, (3) differences in rates of attrition among experimental conditions, and (4) differences in pretest indices for dropouts among conditions. Results of these analyses indicate that cigarette smokers, alcohol drinkers, and marijuana users are more likely to drop out than nonusers, limiting the external validity of both studies. For one project, differential rates of attrition among conditions suggested a possible attrition artifact which will interfere with interpretation of outcome results, possibly masking true program effectiveness. Recommendations for standardizing reports of attrition and for avoiding attrition through second efforts are made.

Axiomatic foundations of a three-set guttman simplex model with applicability to longitudinal data

Collins, L. M., & Cliff, N. (n.d.).

Publication year

1985

Journal title

Psychometrika

Volume

50

Issue

2

Page(s)

147-158
Abstract
Abstract
In this paper the usual two-set Guttman simplex model is extended to three sets. The axiomatic foundations of this extention are presented. Two cases are discussed. In Case 1 there is a three-set joint order, while in Case 2 there is a two-set joint order consistent across all levels of the third set. Case 2 represents the first clear formulation of a longitudinal developmental scale. The model is discussed in terms of its most straightforward application, longitudinal developmental data, and in terms of other possible applications.

Self-initiated smoking cessation among high school students

Hansen, W. B., Collins, L. M., Johnson, C. A., & Graham, J. W. (n.d.).

Publication year

1985

Journal title

Addictive Behaviors

Volume

10

Issue

3

Page(s)

265-271
Abstract
Abstract
The purpose of this study was to examine psychosocial predictors of self-initiated smoking cessation among high school students. Students from nine high schools were pretested using a questionnaire which assessed smoking behavior, beliefs about positive and negative consequences of smoking, moral attitudes toward smoking, normative expectations about smoking, rebelliousness, peer smoking and parent smoking. Smokers identified at pretest were reexamined three months and fifteen months later. Three variables, moral attitudes, peer smoking and positive beliefs about smoking significantly discriminated continuing smokers from quitters at the three-month posttest. Three different variables, negative beliefs about smoking, parental smoking and rebelliousness significantly discriminated between those who quit and later relapsed and those who quit and maintained their non-smoking status at the 15 month posttest. Smoking characteristics at pretest failed to discriminate either those who would quit or those who would maintain their non-smoking status. Results support the development of public information programs which encourage early cessation of smoking which feature the development of appropriate attitudes and beliefs and which foster social support.

Contact

linda.m.collins@nyu.edu 708 Broadway New York, NY, 10003