A Validation of the Sixteen Personality Factor Impression Management Scale and Normative Data for Assessment of Defensiveness in Law Enforcement Applicants Mary Cown, Psy.D., Nick DeFilippis, Ph.D. & Fiona Hill, Psy.D. Georgia School of Professional Psychology

Abstract This study examines validity scale scores of two self-report inventories and the effects of certain variables on the applicants’ response style. This study examines the relationships between the Minnesota Multiphasic Personality Inventory (MMPI-2) validity scales K and L scores and the Sixteen Personality Factor (16 PF) scale Impression Management (IM) score. The scores of the validity scales were also examined with respect to the effects of age (thirty and younger), military experience, and prior law enforcement experience. The present study presented norms and standard deviations for the validity scales among the groups examined. Results indicated that applicants with prior law enforcement experience and who are thirty years of age and younger tend to have slightly higher elevations on all three validity scales. The MMPI-2 validity scales correlated highly with the IM score, lending construct validity to it.

Background The MMPI-2 and 16PF are widely used in the pre-employment screening of law enforcement applicants. A common issue in these types of screenings has to do with elevations on validity scales. Thus, the need for normative data for use of these tests in such settings.

16PF Impression Management Scale The Impression Management scale (IM) of the 16PF purports to reflect defensiveness. However, there are no known validation studies of this scale, using criterion measures. There are also no studies examining norms for this scale in law enforcement settings.

Hypotheses For the purpose of this study, it was hypothesized the IM validity scale of the 16 PF will correlate significantly with the L and K validity scales of the MMPI-2. Also, the scores of the validity scales were examined independently, and the effects of age (< 30), military experience, and prior law enforcement were examined. It is also hypothesized those younger than thirty years of age, and those with prior law enforcement and military experience will score significantly higher on the scales. Based upon clinical experience, younger individuals tend to score higher on these scales, possibly due to lack of skill in these types of interviews and the lack of overall work experience. Additionally, those with prior law enforcement and military experience are hypothesized to yield mildly elevated scale scores. These individuals may be more likely to hold feelings inward, be more authoritarian, rigid, and disciplined and will respond in a more defensive style in order to present themselves in a more favorable manner and not appear weak or deficient.

Method Participants Subjects (n = 360) included men and women in the process of pre-employment psychological screening of law enforcement positions in various cities and counties in the metropolitan area of Atlanta, Georgia. Individuals having prior law enforcement experience included those having been employed as officers in various police and sheriff departments, or as marshals. Military experience included individuals having served in any branch of the military, including the National Guard and Active Reserves for any length of time. All participants were provided informed consent and information regarding confidentiality at the time of assessment. Each participant completed MMPI-2 and16 PF.

Procedure The participants’ data were divided into three groups (categorical variables): 1) military experience, 2) prior law enforcement experience, and 3) age (< 30). The norms and standard deviations for each group were calculated and compared to the remaining group of subjects. The data was also analyzed by comparing the scores of each sub-group to each other and with the entire group. The Pearson correlation was used to identify correlations between the IM scale of the 16 PF and scales L and K of the MMPI-2. t tests were used to assess whether the means of the groups were statistically different from each other.

Results In this study, there was a significant correlation between the L scale and IM (r =.61, p <.001) and the K scale and IM (r =.59, p <.001). Overall, there was a strong, positive correlation between the validity scales (L and K) of the MMPI-2 and the 16 PF (IM). Thus, the first hypothesis was supported. Also, the following variables, prior law enforcement experience, military experience, and age (< 30) were analyzed using an independent samples t test to compare applicants in the aforementioned groups to those applicants with no experience in law enforcement or military, and age over thirty. All groups had mean scores greater than ten points above a T score of 50, which is indicative of a general level of defensiveness.

Results A paired t-test was used to compare participants with prior law enforcement experience and those with no prior law enforcement experience. Those with prior law enforcement experience tended to respond by presenting themselves in a more favorable light than those without such experience. More than 52 % of the total participants had some type of prior law enforcement experience. Also, the age group older than thirty had mildly elevated L and K scale scores, as well as, the IM scale score. Thus, these results suggest that age over thirty and those with prior law enforcement experience tend to have response styles indicative of a general level of defensiveness. Results supported the hypothesis that prior law enforcement experience would have an effect on response styles.

Summary A limitation of this study is that the sample was confined to a certain regional area. Therefore, generalizabilty of the findings is problematic. The inclusion of various geographical districts throughout the United States would be beneficial in providing more comprehensive and culturally based data. Additionally, the exploration of gender and ethnic/cultural differences and educational level would provide beneficial data in future research studies. A strength of this study is its’ uniqueness in assessing the effects of military experience, prior law enforcement experience, and age on the applicant’s response style on the MMPI-2 and 16 PF. Also, the sample size was large. The study provides additional and pertinent information in the response styles of applicants that which cannot be obtained by mere observation of applicants in training or during the probationary period of employment.

Tables L Scale Mean L Scale Std Dev K Scale Mean K Scale Std Dev 16PF IM Mean 16 PF IM Std Dev Overall Sample (N=360) Prior Law Enforcement (N=190) Prior Military (N=102) Under 30 (N=161) Normative Data

Prior Law Enforcement Experience (N=190) No Prior Law Enforcement Experience (N=170) MeasureMSD M t L Scale K Scale PF Prior Law Enforcement Experience

Military Experience (N=102) No Military Experience (N=258) MeasureMSD M t L Scale K Scale PF Prior Military Experience

Over 30 (N=161) Under 30 (N=199) MeasureMSD M t L Scale K Scale PF Over 30 / Under 30

Sample SizePercentage of Total Participants Overall Participants % Prior Law Enforcement Experience % Prior Military Experience % Participants Under % L Scale Mean L Scale Std Dev K Scale Mean K Scale Std Dev 16PF IM Mean 16 PF IM Std Dev Overall Sample (N=360) Prior Law Enforcement (N=190) Prior Military (N=102) Under 30 (N=161) Prior Law Enforcement Experience (N=190) No Prior Law Enforcement Experience (N=170) MeasureMSD M t L Scale K Scale PF Military Experience (N=102) No Military Experience (N=258) MeasureMSD M t L Scale K Scale PF Over 30 (N=161) Under 30 (N=199) MeasureMSD M t L Scale K Scale PF

References Aamodt, M.G. (2004). Special issue on MMPI-2 scale configurations in law enforcement selections: Introduction and meta-analyses. Applied H.R.M. Research, 9(2), Baird, J.S. (1981) Reliability of the 16PF Questionnaire for security guard applicants. J. of Pers. Assess., 45(5), Christiansen, N.D., Goffin, R.D., Johnston, N.G., &Rothstein, M.G. (1994). Correcting the 16PF for Faking: Effects on criterion-related validity and individual hiring decisions. Personnel Psychol., 47(4), Cochrane, R.E., Tett, R.P., & Vandercreek, L. (2003). Psychological testing and the seclection of police officers. Criminal Justice and Behavior, 30, Kornfeld, A.D. (1995). Police office candidate MMPI-2 performance: Gender, ethnic, and normative factors. J. of Clin. Psychol. 51(4), Schnurr, P.P., Rosenberg, S.D., & Friedman, M.J. (1993). Change in MMPI scores from college to adulthood as a function of military service. J. of Abnorm. Psychol. 102,