Questionnaires items

The individual items within a scale are not independent of one another and, for this reason, it is unlikely that one characteristic will change in isolation. However, by dividing up the observed behaviors into several differently formulated questionnaire items, one may create the wrong impression of independence and the equal significance of symptoms. 

Numerical variables can either be continuous or discrete. Continuous variables are measured on a continuous, uninterrupted scale and can take any value on that scale. For example, height, weight, blood pressure, and heart rate are continuous variables. Depending on how accurately we want (or are able) to measure these variables, values containing one or more decimal points are certainly possible. In contrast, discrete variables can only take certain values, which are usually integers (whole numbers). The number of visits to an emergency room made by a person in one year is measured in whole numbers and is therefore a discrete variable. A subject s response to a questionnaire item that requires the choice of one of several specified levels (e.g., l=mild pain, 2=medium pain, 3=severe pain) yields a discrete variable. 

One final common inclusion in many studies of occupational behavioral toxicology and in some test batteries is assessments of symptoms experienced by those exposed to chemicals. While this might be perceived as an ostensibly simple procedure, it entails numerous potential confounds. These evaluations are typically administered via questionnaires. Items for the questionnaire must be carefully constructed with respect to not only the choices of items but also the wording of the text and the manner in which the response is recorded. Clearly, the motivation of the subject in answering the questions must be considered. One problem can arise when the list of symptoms includes only those that are associated with the toxicant of concern. It is necessary to include symptoms that are not associated with the particular toxicant under evaluation so that some assessment of the tendency of the subject to respond positively to all symptoms can be evaluated. Several such evaluations of subjective and mood states are available. The most widely used is the Profile of Mood States (POMS), which consists of 65 adjectives of various moods that the subject answers according to a 5-point rating scale. The POMS has been used extensively in the evaluation of the acute effects of CNS drugs and toxicants. 

Physical health is commonly measured in terms of limitations in the performance of or ability to perform self-care activities (e.g., eating, bathing, dressing), mobility, moderate or more strenuous physical activities, and bodily pain Responses to questionnaire items in this category... 

Tambs K, Mourn T. How well can a few questionnaire items indicate anxiety and depression Acta Psychiatr Scand 1993 87 364-7. 

Figure 13.2 shows the means for the overall value orientations obtained at three different times (pre-test, post-test 1 and post-test 2). In determining the overall mean value, the mean for all the questionnaire items representing egocentric, homocentric and ecocentric orientations (the entire 37 items) are taken into consideration. There is a deereasing trend in the overall score obtained from the pre-test to the seeond post-test. This decrease in the mean value suggests that the pre-serviee teaehers expressed value orientations have... 

Table 10.1 Questionnaire items presented and the related focus group questions...

Each questionnaire item was considered, for example, in terms of... 

Many researchers have constructed items and surveys to measure general chemistry self-efficacy (see Table 1). In the paragraphs that follow, I briefly review those surveys. For example, in the USA, Smist (1993) used six questionnaire items to measure a sample of college students self-efficacy for learning chemistry. The items were administered to the students before and after they took a freshman general chemistry course. The internal consistency of data was high (Cronbach s a = 0.90), but the six items were not constructed to measure students self-efficacy for learning specific chemical concepts. 

In one hundred forty-nine of the enterprises reassessed there is no improvement at all. In the rest, 69 show improvements in less than five of the questionnaire items and 29 show improvements in more than five items. No association was found between improvements in the items and injury rates reduction. 

Positive and negative respondents to the questionnaire items on solvent abuse were scheduled for detailed individual assessment. The individual assessments consisted of three main parts a short interview, a breath test and an extensive battery of psychological tests. 

Figure 18.7 These questionnaire items measure personal perception regarding the safety of an organization and were selected from the Safety Culture Survey developed by Safety Performance Solutions, Inc. With permission.

The basic procedure ran as follows First, the interviewees were shown the conceptual model and the definition of each construct and sub-construct and were asked whether the model and constructs made sense to them. Then, the interviewees acted as judges and sorted the pool of questionnaire items into separate sub-constmcts. The items were divided into two pools because it would be difficult for a judge to sort too many items in one pool. The first pool consisted of items measuring the eleven... 

After two rounds of Q-Sort, 107 items were distributed to six academicians who reviewed each item and indicated to keep, drop, modify, or add items to the constructs. The purpose was to further refine the items and assess whether the items measured the proposed sub-constmcts that they were supposed to measure based on the definitions provided, or whether any additional items were needed to cover the domain. Based on the feedback from the reviewers, items were further modified. Overall, 114 (107 + 7) questionnaire items, including seven items adapted from Li (2002) for the construct of firm performance, were sent out for a large-scale survey (Table 6.11). The large-scale survey questionnaire items are provided in Appendices D and E. 

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