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Biomedical subjects

T Imbos

Publications and source records attributed to T Imbos.

6 recordsLinked to original sources
PubMed1996

The validation of a test to measure knowledge about the fat content of food products.

The objective of the study was to develop and validate a 21-item nutrition knowledge test to measure people's knowledge of the fat content of food-products. After pretesting and provisional development, the test was administered twice to study test-retest reliability. Furthermore, various sub-populations with expected differences in nutrition knowledge completed the test in order to study the construct validity of the questionnaire. The subpopulations consisted of lay-people (N = 81), students of human nutrition and dietetics (N = 108), and professional experts (N = 79) on human nutrition. The internal consistency and uni-dimensionality of the test were determined by calculating the KR-20 statistic and the log-likelihood ratio statistic for the Rasch model. Pearson's correlation and gross misclassification between T1 and T2 were calculated to assess the test-retest reliability. Analysis of variance was used to test for differences in mean knowledge scores between subpopulations. Test-retest reliability was found to be sufficient (R = .85). The internal consistency was moderate (KR20 = .68). According to the Rasch model, two items had to be removed from the test before the log-likelihood ratio statistic of the Rasch model indicated that knowledge about the fat content of food products as assessed by the questionnaire is a uni-dimensional construct. The differences in mean knowledge scores between the subpopulations were significant (p < .01) and in the expected direction (experts > students > lay people). It can be concluded that the test is a reliable and valid instrument to measure knowledge about total fat content in food products and that the Rasch model is a comprehensive method to indicate the reliability of nutritional knowledge tests.

Analysis of Variance↗
PubMed1994

Likert or Rasch? Nothing is more applicable than good theory.

In nursing research many concepts are measured by questionnaires. Respondents are asked to respond to a set of related statements or questions. In unidimensional scaling these statements or questions are indicants of the same concept. Scaling means to assign numbers to respondents, according to their position on the continuum underlying the concept. It is very common to use the summative Likert scaling procedure. The sumscore of the responses to the items is the estimator of the position of the patient on the continuum. The rationale behind this procedure is classical test theory. The main assumption in this theory is that all items are parallel instruments. The Rasch model offers an alternative scaling procedure. With Rasch both respondents and items are scaled on the same continuum. Whereas in Likert scaling all items have the same weight in the summating procedure, in the Rasch model items are differentiated from each other by 'difficulty'. The model holds that the probability of a positive response to an item is dependent on the difference between the difficulty of the item and the value of the person on the latent trait. The rationale behind this procedure is item response theory. In this paper both scaling procedures and their rationales are discussed.

Bias↗
PubMed1990

To what extent are medical interviewing skills teachable?

Growth patterns of medical interviewing skills during a 6-year undergraduate curriculum are assessed by studying 563 medical students taken from five year-groups, interviewing simulated patients. In a cross-sectional, quasi-experimental design their skills are rated by means of the Maastricht History-taking and Advice Checklist (MAAS), an observation instrument which measures five categories of interviewing skills pertaining to initial medical consultations. The findings suggest that the skills for 'history-taking', 'presenting solutions' and 'structuring of the interview' are effectively learned. These learning effects result from a continuous small group teaching program with expert and peer review of videotaped encounters with simulated patients. The teaching effects of this program seem less for the skills pertinent to the phase of 'exploring the reasons for encounter' and to the 'basic interviewing skills', because the students' growing medical knowledge and the increasing ability to solve medical problems exert a counteracting influence on the acquisition of these easily deteriorating skills. The results might be helpful to curriculum planners in order to make their programs for medical interviewing skills more effective.

Cross-Sectional Studies↗
PubMedDate not supplied

Openness to discuss cancer in the nuclear family: scale, development, and validation.

OBJECTIVE: To describe the development and validation of a scale for assessing openness to discuss cancer in the family. METHOD: Two studies were conducted. Study 1 was a cross-sectional study designed to test the factor structure of the scale. Four hundred ninety-eight patients with either breast cancer or Hodgkin's disease were interviewed. In Study 2, a longitudinal study, 133 patients with cancer in the head and neck were tested at four points in time: just before treatment, 6 weeks, 13 weeks and 52 weeks after treatment. Study 2 aimed to confirm the factor structure established in Study 1, to test for construct validity in a new population, to test the psychometric properties of the Openness Scale, and to test the scale's sensitivity to change. RESULTS: In Study 1, a one-factor solution was revealed, resulting in a scale of eight items. In Study 2, the factor structure found in Study 1 was confirmed. In line with theoretical expectations, subjects who perceived their communication about cancer as more open showed more positive rehabilitation outcomes especially at 13 weeks after treatment (less uncertainty, fewer negative feelings, more control, higher self-esteem, fewer psychological and physical complaints). Furthermore, more open communication related with more support by family members and more discussion with the partner. The scale was found to be stable over time. CONCLUSIONS: The scale's construction and subsequent analysis show that open discussion of problems (related to cancer) in the family can be measured reliably with an eight-item instrument. Additional validation of the scale is indicated.

Adaptation, Psychological↗