<p><pre><code> "We find that the constraint imposed by the quota
caused a significant drop in the stock price at the
announcement of the law and a large decline in
Tobin’s Q over the following years, consistent with
the idea that firms choose boards to maximize value."
</code></pre>
The last word "value" in the abstract above is ambiguous; I guess the authors meant "share price". According to other non-monetary measures the "value" of the companies may have gone up. For example, a career path for women could keep them in the companies, making the entire Norwegian workforce more diverse.