Abstract: • The management of obesity is increasingly dominated by nonprofessional self-help groups. Little information about the efficacy of these groups is available from independent sources. In a study of 108 women enrolled in a commercial weight reduction program, we found very high attrition rates; 50% of the members dropped out in six weeks and 70% in 12 weeks. Similar attrition rates have been reported in five other programs in three different countries. Very high attrition rates diminish the effectiveness of commercial weight reduction programs, and they suggest caution in the interpretation of data based on weight losses of persons who remain in these programs. ( Arch Intern Med 1981;141:426-428)

Abstract: The extent and rate of occlusal attrition in relation to degenerative arthritis of the temporomandibular joint were studied in 101 skulls representing early Aboriginal man in Australia Joint degenerations affected 40% of the specimens and were associated with both the rate and extent of tooth attrition Age, unaccompanied by tooth wear, was not significant in the progress of the disease Degenerations affected the temporal joint surface more frequently than the condyle, particularly in the lateral and central regions of the articular eminence Patterns of degenerative joint disease in the Aboriginals illustrated a break-down in the physiological adaptability of the masticatory system resulting from increased occlusal stress consequent upon progressive tooth wear Under these conditions, the teeth and the temporomandibular joints enter a 'wear-out' phase of occlusal function which usually commences in early adult life and becomes more severe as the conditions continue

Abstract: Previous studies repeatedly confirm that attrition rates are very high regardless of the type of psychiatric facility studied. The problems of attrition deserve further investigation since it is clear that offered services are going unused and patients are not getting the help that they need, which in turn has a negative impact on the professionals involved. In our review, we show that most methods of determining attrition rates result in underestimates. We arrive at an attrition rate of 85.4% and present arguments to demonstrate that this high figure is an accurate estimate. Of the 79 variables examined for association with type of termination, 19 reach statistical significance at or beyond 0.05 and a further 17 variables tend toward significance (p ≤ .10). The high proportion of statistically significant findings lends support to the validity of the categorization used to differentiate the two groups of terminators.

Abstract: The 1979 intake to the matriculation studies programme, run by the Department of Extension Studies of the University of Papua New Guinea, has been used as a population for a study on attrition and performance. The study has examined the relationship between two success criteria and several factors with a possible bearing on attrition rates. The factors which turned out to be most important were age, number of children, housing conditions, sex, sponsorship and region of residence.

Abstract: : This paper is an expository survey of some aspects of the theory of Lanchester attrition processes and of applications of these processes in models of theater-level combat. Classical Lanchester differentials-including homogeneous and heterogeneous square and linear laws-are discussed. Underlying assumptions and mathematical forms of analogous continuous time, discrete state space Markov attrition processes are presented. A detailed treatment of a class of simplified ('binomial') attrition equations is given, including underlying assumptions, exact equations for expected attrition and exponential approximations to the exact equations. Applications of the binomial and Markov attrition processes as the basis for attrition calculations in the CONAF Evaluation Model, the IDAGAM I Model, the Lulejian-I Model and the VECTOR-2 Model (4 principal documented models of theater-level combat) are considered.

Abstract: : This report develops a multivariate model describing the effects of individual characteristics, duty location assignments, career turbulence, and military occupational assignments on post-training enlisted male attrition in the Army and Air Force. The report concludes that military occupation and duty location are significantly correlated with attrition, after controlling for individual characteristics. The role of turbulence cannot be distinguished with current measures. Among individual characteristics, high school graduates have much lower attrition than nongraduates in all service occupational areas. Attrition varies insignificantly with mental test category, after controlling for other background and service experiences. Participation in a delayed entry program prior to entering the military substantially reduces the likelihood of post-training attrition.

Abstract: : This report describes a study that examined the relationship between the attrition histories of training platoons and the performance and attrition of Marine Corps recruits differing in high school graduation status. Non-high school graduates placed in platoons with histories of high attrition had especially high attrition rates. This finding replicates the results of an earlier study. The results suggest that the attitudes and expectations of drill instructors may exert critical influences over the performance and attrition of platoons.

Abstract: The concern for attrition in ,higher education has intensified in recent years, although research has demonstrated that attrition rates have not varied drastically over most of the country. The attrition rate has traditionally been higher for the two-year college. Trends concerning gender, aGe, marital status, and ethnic classification are still subject to controversy. Financial factors are generally conceived to be important in persistence. The majority of both dropouts and persisters are derived from the middle socio-economic level, while increased persistence has been associated with higher socio-economic status. In addition, distinction must be made between voluntary withdrawals and failures, since cpUte frequently voluntary dropouts have had higher verbal ability and were more intellectually oriented than persisters who continued progress towards their initial degree objective. High school grade point, high school rank still seems to be the best predictor of college grades, but its relationship to persistence is unclear. However, academic disqualification appears to be a thing of the past. Although academic, health and family, and general dissatisfaction reasons were common, most items were highly varied and dependent on the specific institutional setting, which has led many researchers to develop congruence models to explain these apparent variations.

Abstract: Attrition occurs during the transport and storage of particles and leads to loss of material through dust formation and to environmental pollution. Standard tests are all specifically designed to cater for particular needs and are often indicators of relative hardness than of attrition rates. Since little progress has been made into understanding the mechanisms of attrition, the purpose here is to study one of the basic processes that determines the rate of grinding. The aim is thus to establish a fundamental framework within which past work and future developments can be assessed. An annular attrition cell was designed, constructed and commissioned to permit one of the mechanisms of attrition, namely that in failure zones of deforming solids, to be considered in isolation. Sample weights of 100 gm were more than sufficient and the results were found to be reproducible, systematic and generally independent of sample size. Several close-sized material in the size range 250-2000 µm of various shapes were studied including different grades of sodium chloride, sodium carbonate and molecular sieve beads. The mode of attrition, bodily fracture or surface grinding, was easily verified by microscopic examination of attrited product. Results followed Gwyn's empirical law W = K p t m where W denotes the weight fraction attrited, t time and K p , m are characterising parameters. The reliable data permitted the development of simple kinetic models. One supposes first order loss of coarse material, another that attrition rate is dependent on radius reduction. It may be argued that the former applies to a fracturing mechanism, the latter to a surface grinding process. The first order approach has to be modified to allow for the initial high rate of attrition; the second model may be reduced to the Gwyn form. The attrition cell is useful in characterising materials; it should, in future, permit assessment of equipment performance.

Abstract: We report on correlates of attrition for Blacks and Whites in physician's assistant training programs. The data reveal an unusually high rate of attrition for Blacks (65 per cent) and, in particular, for Black males (59 per cent). This latter group, regardless of educational background and other potential predicators of educational success, encounters significant difficulty in the educational process. An understanding of this attrition phenomenon is useful for designing admissions policies which identify a larger percentage of low risk recruits to health professions education.

Abstract: : The reseacrh reported in this paper represents an attempt to identify 'high risk' attrition factors in first term enlistees. In contrast to previous studies, this research looks at a comparison between soldiers still in the Army, early discharges, and soldiers completing their tour (ETS). The variables being investigated include soldier demographics, job characteristics, work environment, attractiveness of civilian opportunities, quality of location of assignment, and soldier gender.

Abstract: : Underwater Demolition Teams (UDT) and Sea/Air/Land (SEAL) Teams are highly trained combat units within the Navy Special Warfare community. These teams are trained at the Basic Underwater Demolition/SEAL (BUD/S) School, Coronado, CA. Historically, the attrition rate for BUD/S training has averaged 65 percent, most of which is voluntary and occurs early in training. High attrition rates are considered as part of the process of selecting and training the highest quality UDT/SEAL combat swimmers. At the inception of this research project in 1978, however, BUD/S had not produced sufficient graduates to maintain authorized manning levels in fleet Special Warfare units. The primary objectives of this research were to (1) identify factors that relate to BUD/S attrition, (2) develop recommendations that may reduce BUD/S attrition, thereby increasing manning levels in the fleet, and (3) test and evaluate the effect of recommended changes, in terms of attrition and associated costs.

Abstract: In the past only academic variables have performed well in the prediction of attrition. Ideally, persons in higher education would like to predict attrition prior to its occurrence, but many academic variables are not available until after the fact. Thus, the isolation of those motivational and personality variables which identify individuals as "high risk," or potential dropouts is critical. Biographical information can be useful in this context because it is a good predictor of any criterion heavily saturatea vith motivation. To identify academic and nonacademic factors which predict attrition within the college freshman year, biographical information from student questionnaires was assessed. Results demonstrated that dropouts and persisters could be differentiated on the basis of nonacademic background factors. Male persisters had backgrounds of high academic achievement in high school, higher socioeconomic status, and were allowed more freedom by their parents than male dropouts. Female persisters had histories of previous leadership experience, closer relationships to their mothers, and higher academic achievement in high school than female dropouts. Additionally, subgroups of males identified as "high risk" remained stable in terms of their dropout composition over an eight-year period. The findings suggest a strategy for identifying, at the time of admission, whole groups of potential dropouts and for planning some type of intervention to prevent attrition. (Author/JAC)

Abstract: : This research assesses the influence of military environment and individual background characteristics on the likelihood of post-training enlisted male attrition. Post-training attrition refers to recruits who complete their advanced individual training in a military occupational speciality but leave the military before the end of their enlistment term. The study has two objectives. First, we would like to identify the separate influences of individual background characteristics (e.g., educational attainment, aptitude, and family status) and service environment (e.g., military occupational speciality, duty location assignments, and career turbulence) on post-training attrition. Second, we want to determine whether the correlates of post-training attrition vary across services and military occupations. For example, one might expect that if individuals were poorly matched to jobs, then high school dropouts would be more likely to leave early in some jobs than in others. The remainder of this paper is divided into three sections. Section II describes the data set used in the analysis and examines occupational differences in post-training attrition levels. Section III introduces a multivariate model of the attrition process to analyze the separate relative effects of individual characteristics, duty location, career turbulence, and military occupation on attrition. The final section presents conclusions and suggestions for further research.

Abstract: A model designed to predict the risk of attrition for array enlistees who do not have a high school diploma is developed and validated. Parameters of the model were estimated using data on 120,476 ...

Abstract: : This report is one of a series that describes a longitudinal study of a cohort of first-term enlisted personnel to determine how various variables are related to attrition. The purpose of the effort described herein was to determine how various behavioral intentions, attitudes, demographic characteristics, expectations, and performance indices are related to attrition occurring 6 to 7 months after recruit training. Enlisted master record information indicated that attrition between the end of recruit training and 6 to 7 months later was 5.3 percent. The variables most highly associated with attrition were lack of promotions, unauthorized absences, and the perceived honesty of the recruiter. These findings indicated that behaviorally disruptive individuals were generally discharged. Recommendations focused on maintaining closer attitudinal and motivational scrutiny of individuals during their first several months after recruit training.

Abstract: Retention and Attrition Factors of Nonreturning Students at Utah State University by Amy L. Jordan, Master of Science Utah State University, 1981 Major Professor: Keith T. Checketts, Ph.D. Department : Psychology vii The purpose of this study was to determine the factors which affected the decision of students not to return to Utah State University after completion of the previous quarter. The factors were determined by a mailed questionnaire which was a modification of the Withdrawing/ Nonreturning Student Survey developed by American College Testing (ACT). One hundred twenty-two former Utah State University students who had attended fall quarter, 1979 but failed to register for winter quarter were randomly chosen for the study. The students were asked to complete the questionnaire and return it to Utah State University. The return rate through the mail was low and many were completed over the telephone. The results indicated that full-time employment, financial difficulties, marital plans, and the decision to attend a different college or university were the factors cited most frequently as reasons for not returning to Utah State University. viii A recommendation was made for the staff members who work with freshmen to be made aware of the large numbers of these students who do not return to Utah State University. It was also suggested that the distribution system for financial aids be reviewed to determine the most effective utilization of their resources for retention of students. Also, Utah State University may want to explore the special needs of out-of-state students with regard to social life. A study which further investigates the attrition rates of graduate students was recommended. (70 pages)

Abstract: : This thesis was conducted to analyze certain factors effecting first-term attrition from U.S. Naval ships. The Survival Tracking File (STF) was used as the primary data source, and from it files were constructed that permitted three areas of study. First, the overall cohort of a year's worth of first term enlistees was examined. The survival curve for the cohort was generated and individual monthly cohorts were examined for attrition patterns. Secondly, overall attrition percentages were calculated for individual ships and for classes of ships and these attrition percentages were then examined for differences using statistical techniques. An ANOVA model using transformed data proved accurate in explaining attrition variance. Lastly, a comparison between attrition per month and underway hours per month was made for classes of ships and for individual ships of three specific classes. A rough relationship was observed, for certain classess of ships, between peaks of high underway hours and peaks of attrition. In looking at individual aircraft carriers, the attrition percentage seemed to be inversely proportional to underway hours per month. Several of these findings warrant further investigation so that the Navy may more fully understand it attrition problem and thereby take steps to alleviate it. (Author)

Abstract: : The purpose of this thesis was the development of a first-term attrition severity index for 85 United States Navy enlisted ratings. The multiattribute model utilized in the development of the index was constructed using five rating-specific factors: (1) attrition, (2) replacement cost, (3) size (number of personnel in the rating), (4) shortage or excess of billet requirements, and (5) priority. The model provided first-term attrition severity indicators for the 85 ratings included in the study, indicating the diverse impact of attrition across Navy ratings and providing a practical basis for assigning scarce manpower resources to enlisted ratings experiencing the most severe effects of first-term attrition. (Author)

Abstract: : A statistical analysis was conducted to assess the effectiveness of the experimental program, RTC CREDO, to counter first-term enlisted attrition in the Navy. The results of this study demonstrate that the RTC CREDO experiment was successful in reducing first term enlisted attrition by 1.22 percent after 14 months of service when compared to a control group. This difference was not statistically significant at the .05 level. The reduction in attrition gained by the RTC CREDO experiment appears at this time to be inefficient with respect to the cost of the program. It is recommended that the RTC CREDO program in its present form and with its present contribution toward reducing first-term attrition be discontinued, unless the difference between control group and CREDO attrition rates increases markedly by the time the cohort finish their first enlistment periods. (Author)

Abstract: The war of attrition with random rewards (WARR) has been examined by Bishop et al. (1978) who, on the assumption of independent rewards for the protagonists, specified the precise form of the evolutionarily stable strategy (ESS) in the case of a finite number of reward values, and, by a limiting argument, in the case of a density of reward values. Riley (1979), on the other hand, considered the latter case, using a variational technique. In this presentation, and in Bishop and Cannings (in preparation), we apply this latter technique to models of the form, (E (x, y) being the payoff),

Abstract: The lack of theoretical models has long plagued researchers in the area of student attrition. The models of Tinto, Spady, and Rootman in the area of student attrition, and models of student participation, status attainment; turnover in work organizations, suicide, and the relation between intentions and behavior are presented and discussed. A synthetic model incorporating selected elements from these models is developed and presented. In one study the variables in this model accounted for about 50 percent of the variance in dropout for university freshmen. THE SYNTHESIS OF A THEORETICAL MODEL OF STUDENT ATTRITION