Critical job events, acute stress, and strain: a multiple interrupted time series.

A critical job event (CJE) is defined as a time-bounded peak of performance demand made on the individual as an integral part of his job. Though such events are an important source of acute job stress and are amenable to longitudinal study, relevant research has been scant. In the present study, the effects of acute objective stress on subjective stress and on psychological and physiological strain were assessed among 39 first-year nursing students in an interrupted time series with multiple replications. Strain was measured five times, twice in anticipation of CJE interspersed by three low-stress occasions. The CJEs were providing the first comprehensive patient care and the final exam in nursing. A consistently confirmatory pattern of significantly rising and falling strain was found for anxiety, systolic blood pressure, and pulse rate: qualitative overload and serum uric acid changed as predicted four times out of five. CJE research can redress past overemphasis on chronic organizational stress and strengthen causal interpretation.