Methodology

The study is based on a panel dataset containing information for 248 publicly listed Norwegian firms from 2001 to 2009. To compile the dataset, the authors collected the names of all public limited Norwegian firms that traded on the Oslo Stock Exchange anytime from 2001 to 2009. Data on CEOs and board members was collected from annual reports and other publicly available records. The authors used data on companies and board members of firms in Denmark, Finland, Sweden, and the United States to construct comparison groups for some of the tests. Tobin’s Q (defined as the ratio of the market value of a firm to the replacement cost of its assets; a ratio above 1.0 indicates that a firm is valued higher than the replacement cost of its assets) serves as the main measure of firm value in the analysis.

The authors evaluate several research questions with varying statistical methods. The authors use instrumental variable analysis to evaluate the whether firm values improve or decline as a result of the new board structure mandate, to assess the quota’s long-run firm value over the period when firms implemented the mandated board changes, to assess how the quota impacted board characteristics, and to evaluate the effect of gender quotas on firm policies. The authors then use difference-in-difference techniques to evaluate the effect that the announcement of the gender quota has on stock prices. Finally, the authors use multivariate regression analysis to compare new, retained and exiting directors by gender, and examine the effect of the gender quota on incorporation rates.