Left to their own devices, humans tend to fall prey to biases that make them poor decision makers. For instance, among other foibles, most purchasing managers routinely under-order. In fact, past research has shown that managers are typically 10 to 20 percent off the mark when it comes to ordering the optimal quantity of products.

However, somewhat surprising, the same research has also shown that this suboptimal ordering only results in a 1 to 5 percent loss in expected profit. This conundrum has left many an executive with a dilemma. As the CEO of a medium-sized online florist shop told me: “I cannot micro-manage all my people. Before I go and intervene, I need to know the impact on my business.”

Fair point. Managers who base purchasing decisions on their gut feelings—either because they have never devised a rational ordering policy or regularly choose to override it—make a lot of mistakes. But if it only costs the firm about 1 percent of extra profit, executives may be reluctant to stir the pot. In most SMEs, a CEO’s path is strewn with seemingly juicier projects in terms of ROI.

 …