Interruption and Type A behavior as causes of overload in police radio dispatchers were examined in this observational study. All of the dispatchers (N = 72) were observed throughout one work shift, and about one half of the sample were observed for two additional shifts. For each work activity, observers recorded whether it was finished before the next activity was begun (sequential processing), left unfinished so that the dispatcher could attend fully to a new demand (preemption), or processed but ultimately left unfinished while the dispatcher simultaneously attended to one or more new demands (simultaneity). Analysis revealed that subjects who more often had their activities pre-empted or who handled demands simultaneously appraised their work as more overloading and took more coping actions. The effect of objective work volume on appraisal was indirect, mediated by interruption. Regardless of the level of interruption, Type A subjects proved to have lower thresholds for appraising demands as overloading and taking coping actions than did Type B subjects. These findings implicate interruption as a critical factor in job stress among human service professionals and also demonstrate the importance of measuring objective work demands in studies of this phe-nomenon. Police dispatchers play a critical role in police effectiveness in

This paper reports on the findings of a piece of research work aimed at investigating and analysing the impact of