Assessment, Statistics, and Research

Who would think that a simple statistic like a mean or a median would make a difference? In large samples involving thousands of people, and when data are normally distributed (close to the shape of a bell curve), the mean and median will be nearly the same. In fact, in a theoretical distribution called the normal curve , the mean , median , and   mode are in the middle. But, many samples are not normal distributions . Instead, the often contain extreme scores called outliers or a lot of scores bunched up at high or low levels ( skewed ). Sadly, even people that understand statistics, continue to report the mean as if they are not thinking about their samples. Suppose you work for a company where the top person earns $300,000 but most folks earn $30,000 to $60,000. Well that $300,000 is gonna skew results and the mean will look much higher than the median. I ran some fictitious data on a sample of 10 people. Nine earn between $30 and $60K and one earns $300K. The Mean = $6

The Schwartz Outcome Scale (SOS ) has the potential to be a useful measure of counseling outcomes. Overview I and my colleagues used the 10-item version of the Schwartz Outcome Scale in two recent studies about psychotherapy patients. The scale measures several aspects of well-being:  physical, relational, and psychological functioning and the person’s capacity to be peaceful, interested, excited, and satisfaction with life. RELIABILITY In our two studies, coefficient alpha  reliability values were .93 and .96 (Sutton et al., 2018). VALIDITY In previous research, the SOS was linked to hope, self-esteem, affect, mental health, and life satisfaction    (Young, Waehler, Laux, McDaniel, & Hilsenroth, 2003). Some validity findings based on positive correlations with other measures may be of interest to clinicians and researchers (Sutton et al. (2018).    Satisfaction with counseling .63    Likely to return to counseling .56    Spiritual well-being .84    Bi

  What makes a test valid? is a tricky question.  The short, and rather obnoxious response is, “nothing.”  Like reliability , validity is a property of test scores  rather than tests but more accurately, an interpretation of the scores. But it is important to take the question seriously when test-takers and users are wondering how much confidence to place in a test score. As with many aspects of science, the answers can be simply stated but there is a complicated backstory. Validity Traditions For many, the traditional views of test score validity will be sufficient. Tests measure constructs. Scientific constructs are ideas that have features that can be measured like reading comprehension, dominance, short-term memory, and verbal intelligence. Construct validity is not a single entity but rather the current state of knowledge about how a test instrument’s scores have functioned in many settings and in relation to criteria. Construct vali