Stalking is generally described as the willful, repeated, and malicious following, harassing, or threatening of another person. Many studies have showed that stalking evolves from pathological attachment. The purpose of this study was to assess the psychometric properties of the Stalking Propensity Scale (SPS), a new measure of the typical personality traits and behaviours of stalkers. We supposed to measure four dimensions: Following and harassing behaviours, Impulsiveness and aggressiveness, Needs of intimacy. We investigated also the relationship between stalking phenomenon and attachment styles.
All participants provided information about age, sex, gender, educational level and professional activities. Our sample consisted of 193 subjects, 98 males and 95 females. The age of participants ranged from 19 to 61 years, with a mean of 32 years (DS = 9,5). They completed the Stalking Propensity Scale (SPS) and the Psychological Treatment Inventory Attachment Styles Scale (PTI-ASS). We used factor analysis to assess the dimensional structure of the SPS. Thus, an Exploratory Factor Analysis (EFA) with Principal Axis Factor (PAF) analyses was conducted. To verify the reliability of the test, the Cronbach’s alpha coefficient was calculated. The Concurrent validity was assessed by correlations between the SPS dimensions and the PTI-ASS.
Exploratory Factor Analysis (EFA) showed a structure composed by three principal factors: following and harassing behaviours, Impulsiveness and aggressiveness, and Needs of intimacy. Four items were excluded because they showed communality values less than .30. The three scales of the SPS showed a good internal consistency ranging from alfa =. 85 (Following and harassing behaviours) to alfa =. 77 (Impulsiveness and aggressiveness). The Cronbach’s alpha coefficient of the total was .87 (Table III). Correlations between the scales and the PTI-ASS dimensions were statistically significant. In specific, the Following and harassing behaviours was correlated with the Preoccupied (r = .49; p < .01) and the Disorganized styles (r = .53; p < .01), Needs of intimacy showed correlations with Avoidance (r = -.42; p < .01) and Preoccupied styles (r = .30; p < .01), and Impulsiveness and aggressiveness with Preoccupied (r = .39; p < .01) and Disorganized (r = .50; p < .01) (Table IV).
Our results demonstrated a three factors structure of the SPS. The scale shows good psychometric qualities: reliability values of the three scales are adequate. Correlations between SPS scales and the PTI-ASS dimensions indicate the good concurrent validity of the instrument. These findings suggest that the SPS may be useful for those who work in forensic and mental health to identify potential stalkers and to understand better stalking phenomenon. Further work is needed to replicate our results, not only in a larger samples of individuals, but also in clinical populations.