Hic Sunt Dracones: On the Risks of Comparing the ITCV With Control Variable Correlations
指出管理学者常用来检验结果稳健性的ITCV与控制变量相关性比较存在三个问题：尺度不同、需用无条件ITCV、多变量干扰使解释复杂，并用模拟和实例证明经验法则有误导性。
To examine the robustness of their results against omitted variable bias, management researchers often compare the Impact Threshold of a Confounding Variable (ITCV) with control variable correlations. This paper describes three issues with this approach. First, the ITCV and control variable correlations are measured on mathematically different scales. As a result, their direct comparison is inappropriate. Second, a fair comparison requires a rescaled version of the ITCV known as “the unconditional ITCV.” Third, even the interpretation of the unconditional ITCV is complicated by the presence of multiple omitted variables, numerous control variables, and correlations between the omitted and control variables. We illustrate these issues with simple computer-generated data, a Monte Carlo simulation, and a practical application based on a published dataset. These results suggest that rules of thumb based on ITCV and control variable correlations are misleading and call for alternative ways of running, interpreting, and reporting the ITCV.