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.

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.

In this study the effect of the reduced distribution of study activities on students' conceptual understanding of statistics is investigated in a quasi-experiment. Conceptual understanding depends on coherent and error free knowledge structures. Students need time to construct such knowledge structures. A curriculum reform at our university resulted in statistics courses which were considerably shortened in time, thereby limiting students' possibility to distribute study activities. Independent samples of students from before and after the reform were compared. To gauge conceptual understanding of statistics, students answered open ended questions in which they were asked to explain and relate important statistical concepts. It was shown that the reduction of distributed practice had a negative effect on students' understanding. The finding that condensed courses make it more difficult for students to reach proper understanding of the subject matter is of interest for anyone who is engaged in reforming curricula or designing courses.

This study investigated the effects of four instructional methods on cognitive load, propositional knowledge, and conceptual understanding of statistics, for low prior knowledge students and for high prior knowledge students. The instructional methods were (1) a reading-only control condition, (2) answering open-ended questions, (3) answering open-ended questions and formulating arguments, and (4) studying worked-out examples of the type of arguments students in the third group had to formulate themselves. The results indicate that high prior knowledge students develop more propositional knowledge of statistics than low prior knowledge students. With regard to conceptual understanding, the results indicate an expertise reversal effect: low prior knowledge students learn most from studying worked-out examples, whereas high prior knowledge students profit most from formulating arguments. Thus, novice students should be guided into the subject matter by means of worked-out examples. As soon as students have developed more knowledge of the subject matter, they should be provided with learning tasks that stimulate students to solve problems by formulating arguments.

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.