Personality Inventories: Reliability, Validity, and Correlation - Essay Example

The GESS questionnaire is an adaptation of Hale, Fiedler, and Cochran's 25 item inventory (Hale, Fiedler & Cochran, 1992). This inventory is a measure of the optimism that an individual possesses concerning the likelihood of achieving goals in life.

A person with a high GESS score has a great degree of optimism in their own ability to complete a task. While a person with a low GESS score is considered to be pessimistic about their own ability to reach the desired goal.MethodsParticipants were selected randomly from the classroom. Of the 17 subjects participating in this study, 6 were male and 11 were female. Ages ranged from 19 to 30 years old. Two personality inventories were used in this study, the Internal Control Index and the Generalized Expectancy for Success Scale.

Each test subject was seated in a relatively quiet and secluded environment and asked to fill in the answers on the two separate inventories.ResultsThe results of the first administration of the test questions are shown in Figure 1. GESS numbers and ICI numbers were calculated by hand scoring each questionnaire. GESS scores ranged from 86 to 149, out of a possible range of 30 to 150. ICI scores ranged from 67 to 136, out of a possible range of 28 to 140. It is interesting to note that the lowest two scorers on the GESS were also the lowest two scorers on the ICI.

From the given analysis, it cannot be determined if age had any effect on the scores. A scatter plot of the results is shown in Figure 2. GESS scores are plotted along the x-axis and ICI scores are plotted along the y-axis. The mean of the GESS Scores is 122.3, and the standard deviation is 17.4. The mean of the ICI Scores is 109.9, and the standard deviation is 16.3. The slope of the best-fit line connecting these data points is 0.6. If there was a perfect correlation between the two personality inventories, the slope would be 1.0. If there was a perfect reverse correlation, the slope would be -1.0. It is important that the standard deviation is a significant percentage of the mean GESS score.

This illustrates that there is a continuum of people who fall between the extreme classifications of optimist and pessimist. Similarly, the standard deviation of 16.3 for the ICI Scores shows that there is a range of people who fill the spectrum as being classified from "Internal" to "External". The similarity between the standard deviation of 17.4 for GESS and 16.3 for ICI helps to build a case for a strong correlation between these measures.ReferencesDuttweiler, P.C. (1984). The Internal Control Index: A Newly Developed Measure of Locus of Control.