You will recall that recruitment and selection is essentially about accuracy in prediction. The aim is to take on board a candidate who is going to succeed and perform well. The table at the start of this chapter showed that several forms of selection testing had much higher predictive success than conventional recruitment methods. Internal assessment centres are top of the league, while ability tests, assessment centres for external candidates and personality tests all do better than the traditional interview. That is why so much attention has been directed in recent years into analysing and refining tests and their results.

The first advocate of selection tests was Samuel Pepys, the famous 17th century diarist who, when secretary to the navy, proposed and outlined a more systematic assessment of ability than the nepotism currently rife. It was some time on from here before they began to be developed and adopted, firstly in America in the early part of the 20th century before they began to be more widely utilised in the Second World War in the UK when soldiers were people selected for officer potential. After the war, the ideas and methods were applied in the Civil Service but Figure 5.2 shows that the explosive growth in their use did not begin until the late 1980s.

There are more than 1000 tests available on...