Requirements for SHE performance indicators

In Part IV, we will review different types of SHE performance indicators for use in feedback control. Table 11.1 shows the basic requirements that such indicators must satisfy (Tarrants, 1980). 

The first four criteria are derived from feedback-control theory. A SHE performance indicator must be observable and quantifiable, i.e. it must be possible to observe and measure performance by applying a recognised data-collection method and scale of measurement. The nominal scale is the simplest type. This means that we must be able to tell whether the result represents a deviation from a norm or not. Usually, the SHE performance indicators are expressed on a ration scale of measurement. A typical example is the LTI-rate, i.e. the number of lost-time injuries per one million hours of work. 

The SHE performance indicator must also be a valid indicator of the risk of loss. We are especially concerned with so-called criterion-related validity. We have to ask whether the SHE performance indicator actually measures what we intend to measure, in our case the risk of losses due to accidents. Since accidents are rare events, we also look for other types of SHE performance indicators such as the frequency of unsafe acts and conditions. In risk analyses, we predict the frequency and consequences of accidents. Accident statistics are then used to validate the methods (Suokas, 1985). 

The SHE performance measure must be sensitive to change. It must allow for early warning by capturing changes in an industrial system that have significant effects on the risk of losses due to accidents. The indicator must also be compatible with other performance indicators to prevent the decisionmakers receiving contradictory control signals. 

We now move to criteria derived from theories on human information processing and organisational learning. The SHE performance indicator must be transparent and easily understood in that its meaning is apparent and compatible with the users s theoretical understanding and unconscious mental models. 

---