Catrien Bijleveld

Fitting Longitudinal Reduced-Rank Regression Models by Alternating Least Squares.

An alternating least squares method for iteratively fitting the longitudinal reduced-rank regression model is proposed. The method uses ordinary least squares and majorization substeps to estimate the unknown parameters in the system and measurement equations of the model. In an example with cross-sectional data, it is shown how the results conform closely to results from eigenanalysis. Optimal scaling of nominal and ordinal variables is added in a third substep, and illustrated with two examples involving cross-sectional and longitudinal data.

It Takes Two to Do Therapy: On Differential Aspects in the Formation of Therapeutic Alliance

For two therapies the dependence of the therapeutic alliance on the indices of the alliance of the partner is studied using multivariate dynamic analyses. The proposed model starts from the assumption that it is mainly the patients alliance that is dependent on the therapists alliance indicators, although the reverse relationship is considered as well. From videotapes, ratings of the achieved alliance had been made by two methods, the Penn-Helping Alliance Scales (Penn-HAS), and the Therapeutic Alliance Rating System (TARS). Whereas for the Penn-HAS the overall ratings for the patient and therapist were strongly mutually dependent, the dependence for the TARS was less strong, requiring more in-depth analyses based on the factor scores of the original ratings.

STRESS-RELATED PSYCHOPHYSIOLOGICAL REACTIONS OF TRUCK DRIVERS IN RELATION TO ANXIETY, DEFENSE, AND SITUATIONAL FACTORS

A system analytic frame of reference is chosen for analysing interindividual differences in driving a technically optimised tank-lorry in comparison to a standard tank-lorry. Seven professional tank-lorry drivers were tested with psychological tests, and their test results were related to physiological measures assessed under different driving conditions in both lorry types. Two dimensions were used to explain the pattern of interactions between the independent (psychological and situational) and dependent (physiological) variables. It is argued that beyond technical improvements, also taking into account information on personality variables and situational factors is a promising approach to accident prevention research.

Positive and negative aspects of the work of information technology personnel: An exploratory analysis

This paper re-analyses data gathered in a 1989 research among Dutch information technology personnel. Working from Karaseks job stress model, we use exploratory multiple correspondence analyses on the aggregated data matrix of occupations and work items. We employed two models: one that emphasised the negative evaluations of job aspects, and one that emphasised positive evaluations. The structuring of positive evaluations of job aspects proved most meaningful. Occupations could be distinguished into three groups. The first and largest group is characterised by a fairly balanced degree of autonomy and workload. A second group comprised of middle management occupations is characterised by unfavourable judgement on workload, matched by insufficient autonomy; as such, employees in these occupations appear at risk of overburdening. A third group of computer specialists report a workload that is too slight given their degree of autonomy; this group appears to be at risk of underburdening.

Daily menstrual symptom measures in women and men using an extended version of Moos's instrument

Symptoms of well-being and of distress were studied in normal men and women by daily administration of an extended version of Mooss menstrual distress questionnaire (MDQ), Form T. Measurements were collected for 35 consecutive days, and answers for men, women using oral contraception (OC), and women using no oral contraception (NOC) compared. It was shown that items asking after well-being play an important role in describing mood fluctuations during the menstrual cycle. OC women reported less water retention than NOC women did but, contrary to expectation, OC women reported more abdominal pain than NOC women. No average differences in intra-individual variation between NOC and OC women were found. On average it was only on the abdominal pain and water retention subscales that men showed less intra-individual variation than women.

Working conditions and mental strain of automation personnel

In 1989 a questionnaire was administered to approximately 3,000 persons employed in the automation sector in the Netherlands. The aim of this enquiry was to make an inventory of possible stressful aspects in the career and working conditions of automation personnel. Using multiple correspondence analysis, risk factors and occupations at risk were identified. It appears that middle‐management occupations are at risk concerning stress; occupations in lower management and teachering seem to be at risk concerning career prospects.

Is the worst of the epidemic over? Back calculation of HIV seroprevalence in The Netherlands

This article calculates back the HIV seroprevalence in the Netherlands from AIDS cases notified 1982-1990 and rates of progression from HIV to AIDS adopted from American studies. It discusses a number of problems, such as changing AIDS definitions and the possible impact of AZT treatment. We estimate that the Netherlands had approximately 6762 HIV seropositives by the end of 1988, which is considerably lower than earlier expectations. When a hypothetical decrease of 10% in the manifestation of AIDS cases due to AZT treatment was incorporated, the estimate for the end of 1988 becomes 7549. After deduction of the AIDS patients who had died by the beginning of 1989 from this estimate, the HIV seroprevalence by the end of 1988 is approximately 7000. The distribution of seroincidence over time suggests that the HIV epidemic in our country has passed its summit and that the HIV incidence is falling quickly. The question arises as to how far this fortunate development may be considered a success of the Dutch AIDS policy, a policy characterised by more openness than in many other countries. The material studied here, however, allows no definite answer to this intriguing question.