Do you want to improve your process for selecting church planters? If the answer is yes, let’s begin by considering this hypothetical situation.
Your denomination or church network plants 100 churches. As the director of church planting, you hire the first 100 candidates who apply. After two years into their ministries, 15 of these church planters are demonstrating success. Of course, the definition of success is up for discussion and interpretation. However, for the sake of illustration, let’s say that the 15 churches continue to grow numerically and show vitality, while the remaining 85 churches either have closed or are seriously struggling to survive.
This statistic is the base rate (the proportion of individuals evaluated as successful church planters using your current selection procedures). Without a rigorous selection system, we can expect 15% of individuals from a normally distributed population to succeed as church planters.
As the director, you decide that you would like to improve significantly on the number of church planters who are successful. You then institute a rigorous selection system—one that discriminates fairly (see my previous blog post). Using this new system, you only hire 10 out of the next 100 individuals who apply. This statistic of 10% is your selection ratio (the number of individuals selected as church planters relative to the total number of applicants).
Now the critical question that concerns you is this: Does a rigorous selection system make a difference in the proportion of church planters who are successful? After two years into their ministries, you find that 9 of these 10 church planters (or 90%) are successful. This statistic is your hit rate (the proportion of selected individuals who subsequently are evaluated as successful).
The final question is this: How much better is your selection process for having implemented a rigorous system? To be of any use, the selection process must improve on the base rate. If we subtract the hit rate from the base rate, 90-30, we can reasonably conclude that the new process improves selection by 60%. This statistic is your incremental validity (the degree of improvement over the base rate). The gain in validity results from adding new predictors to the existing selection process.
Demonstrating incremental validity is a desirable outcome. In future blogs, I will explore various issues, concepts, and principles about personnel selection. These commentaries are intended to help you improve your selection decision-making.