ABSTRACT
The lost-time injury frequency rate (LTI rate) used to be the most common indicator of safety performance. The LTI rate has been criticised on a number of grounds, among them that it is relatively easy to manipulate. Many companies use the so-called total recordable injury frequency rate (TRI rate) instead. This chapter focuses on the use of the TRI rate. It also looks into the principles of analysing time series of the TRI rate and the control chart for the TRI rate, and discusses the merits and shortcomings of safety performance measures based on the LTI and TRI rates in general. The suitability of the LTI rate and later the TRI rate as safety performance measures has been extensively debated among researchers and practitioners in what is called the 'safety measurement problem'. The 'problem' is visualised in an evaluation of the LTI and TRI rates by use of the requirements that safety performance indicators need to satisfy.
