What is the true statement, related to stability reliability? ...

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What is the true statement, related to stability reliability? (Select all that apply.)
 
  a. It is useful for establishing the validity of a physiologic measure.
  b. It establishes the consistency of repeated measures of the same attribute with the use of the same scale or instrument over time.
  c. It reveals random error but not systematic error.
  d. It is sometimes referred to as test-retest reliability.
  e. It may be difficult to interpret whether a measurement has unacceptable stability reliability or whether maturation has affected subjects' responses.

Question 2

For a multimethod measure, a researcher measures anxiety using a 0- to 10-point verbal scale, the Spielberger State-Trait Anxiety Inventory (0 to 40 points), and systolic blood pressure readings (80 to 300 points).
 
  What are logical strategies for using these three pieces of information gathered from each subject? (Select all that apply.)
  a. Add up all three numbers for a total score.
  b. Rank all three measures as 1-high, 2-medium, and 3-low, and sum the result.
  c. Determine the most accurate measurement and give it more weight than the others in a ranking.
  d. Determine the most accurate measurement in the first few subjects and then use it exclusively.
  e. Report the numbers individually without summing them.

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Answer to Question 1

ANS: B, C, D, E
Stability reliability is concerned with the consistency of repeated measures of the same attribute with the use of the same scale or instrument over time. It is usually referred to as test-retest reliability. Because it measures the same variable in the same manner, it reveals only random error, not systematic error. Test-retest reliability requires the assumption that the factor being measured has not changed between the measurement points. Many of the phenomena studied in nursing, such as hope, coping, pain, and anxiety, do change over short intervals. Thus, it is difficult to determine whether change represents measurement error or valid change.

Answer to Question 2

ANS: B, D, E
Another effective means of diminishing systematic error is to use more than one measure of an attribute or a concept and to compare the measures. To make this comparison, researchers use a variety of data collection methods, such as scale, interview, and observation. Campbell and Fiske developed a technique of using more than one method to measure a concept, referred to as the multimethod-multitrait technique. Multimethod measurement strategies decrease systematic error by combining the values in some way to give a single observed score of anxiety for each subject. Sometimes, however, it may be difficult logically to justify combining scores from various measures.