Construct validity of some unweighted product‐count diversification measures

Construct validities are assessed for three simple‐to‐compute, unweighted, SIC‐based continuous diversification measures and a recently proposed two‐dimensional, SIC‐based categorical diversification measure. Two of the three continuous measures are found to correspond strongly to Rumelt's categorical measures, suggesting that these two objective and easy‐to‐calculate measures are better suited for large sample, strategy research than has previously been assumed. No support is found for the two‐dimensional measure.