(WITHDRAWN) Understanding the Effects of Work Shift on Workplace Violence in Canada: A Propensity Score Matching Approach

Introduction

Employees’ exposure to workplace violence has been linked to a variety of negative outcomes, such as decreased job satisfaction, poor mental wellbeing, and high turnover rates. As an important work environment factor, work shift has been understudied as to how different work shifts (e.g., night shifts/casual schedules) may influence employees’ experience of violence at work. Adopting a propensity score matching approach, the present study sought to examine the effects of work shift on employees’ exposure to violence in the Canadian workplace by gender.

Methods

Data came from the Canadian General Social Survey on work and home (2016). A total of 8,187 employed adults (aged 25 - 64; 4,281 women [52.3%]; 3,906 men [47.7%]) were analyzed. Independent variable was work shift, including three categories: (a) regular daytime, (b) night shifts, and (c) daytime irregular shifts (e.g., rotating shifts, on-call, or casual employment, etc.). The regular daytime group was the comparison/control group (female: n = 3,284; male: n = 2,872). One treatment group included workers on night shifts (female: n = 176; male: n = 228), and the second treatment group comprised of those on irregular daytime schedules (female: n = 821; male: n = 806). “Statistical twins” were drawn from the comparison group to match observations in the two treatment groups, respectively. Nearest-neighbor matching with replacement (Caliper = 0.2 of the standard deviation of the probit of the propensity score; Austin, 2011) was adopted to balance covariates (age, education, income, social class, marital status, visible minority status, workplace size, number of hours worked per week, and number of weeks worked last year). Female and male groups were matched and analyzed separately. After matching, sufficient balance on all covariates was achieved for both female and male subsamples. Negative binomial regressions with robust error variance were then used to estimate the effects of night shift and irregular daytime schedule, respectively, on workplace violence, a count variable constructed as the total number of varied forms of violence experienced at work in the past year (i.e. verbal abuse, sexual assault, physical violence, humiliating behavior, and threatening).

Results

For the female subsample, compared with their counterparts on daytime regular schedules, the night shift treatment group reported a higher incidence rate of violence (IRR = 1.67, SE = 0.28, p = 0.002); the irregular daytime schedule group also reported a higher incidence rate of violence (IRR = 2.25, SE = 0.17, p = 0.000). For the male group, working on a night shift did not lead to increased exposure to violence (IRR = 1.02, SE = 0.2, p = 0.922). Those who were on irregular daytime schedules, however, reported a higher incidence rate of violence at work (IRR = 1.54, SE = 0.15, p = 0.000).

Conclusions/implications

Findings suggest that employees, especially women, on non-daytime regular work schedules are more vulnerable to workplace violence, and hence should be given further attention in the advocacy work for workplace safety and equity. The presentation ends with policy and research recommendations in the context of anti-workplace violence.