Multiple Sclerosis
...rchers cannot be completely sure of the honesty of the participants, since the survey was completed in the privacy of their home with as little stress as possible, they would have no reason to assume that the respondents were untruthful in their answers. Concerning external validity, an aspect that may present a possible issue for this is the fact that an in tact group was used by the researchers. Because the list of potential participants was obtained from a chapter of the National Multiple Sclerosis Society, the sample may be biased towards those individuals who have better access to resources and have sought group help for their condition, thus decreasing the ability to generalize the results of the study to the population as a whole. Control & Manipulation: Control in this investigation was primarily a factor of ensuring each of the participants completely the exact same questionnaire, which was obviously not difficult to achieve as they were all mailed the same informational packs. The conditions that the participants completed the surveys in could not have been controlled as they were filled out in each individual’s home. Measurements: The measurements of the questionnaire were reported by participants through the use of a 7 point scale ranging from 1 (totally unsatisfying) to 7 (completely satisfying) as a quality of life scale. This quality of life scale had previously been used in research and had been found to have a high degree of internal consistency and was selected for this study due to its focus on psychosocial functioning. Furthermore, the questionnaire included a demographic and illness-related items section that included both fixed and open response areas that were utilized to acquire information regarding personal aspects of the participants life that were used as independent variables. These variables were then compiled and their effect examined on the dependent variable of quality of life. Sample Characteristics: The population sample that was asked to take part in this questionnaire included 478 people and was compiled from a random list from the membership rolls of a regional chapter of the National Multiple Sclerosis Society. Of the people asked to participate, 227 (47%) people returned the questionnaires. This sample represents a sort of in tact group as the list was generated from a membership log of the society mentioned above. While this probably detracts from random assignment of groups, it was also the most suitable method of ensuring the people contacted for participation were indeed suffering from multiple sclerosis. The sample was made up of people residing in a large industrial state located in the Midwestern United States ranging from 20 to 79 years of age with a mean of 47. Furthermore, of the respondents, most were Caucasian women that were married, well-educated, and lived in urban or suburban areas. Reliability & Validity: In examining the reliability of this study, the seven point quality of life scale that was used in this study had previously been used by Chibnall and Tait in a 1990 study dealing with the quality of life in people with chronic illness. In this study, the scale was found to have a high degree of internal consistency (Cronbach’s alpha = 0.91) and also an sufficient test-retest reliability (r = 0.73, p < 0.001). Nature of the Observations: Observations in this study were made through the compilation of data collected from mailed copies of the questionnaire discussed above which included a letter from the service coordinator of the regional National Multiple Sclerosis Society chapter, and a stamped, self-addressed envelope for the return of the completely survey. Confoundings: Issues involving threats to internal validity in this study involve a number of potential problems. First, only one type of instrumentation was used in examining quality of life among the participants, placing a limit on the construct validity as there nothing available for comparison with the instrument to evaluate how well it was able to measure was it purported to. While this poses a potential threat, the scale that was used in the questionnaire was found to be adequately rel...