The document discusses Principal Financial Group's use of non-GAAP financial measures to evaluate performance. It states that these measures are useful for investors to understand the company's normal operations, but are not a substitute for GAAP measures. The company provides reconciliations between non-GAAP and GAAP measures. Management also uses non-GAAP measures for goal setting and compensation. Certain operational measures like assets under management are not considered non-GAAP financial measures.