Women in Canada at the end of their reproductive years have on average about 0.5 fewer children than they desire, according to new research.

A survey of nearly 3,000 women aged 18 to 44 conducted by Lyman Stone of the Cardus think tank explored family and fertility preferences, expectations, and outcomes.

He found that the number of women “missing” births vastly outnumber those reporting “excess” births. Indeed, nearly half of all women at the end of their reproductive years have had fewer children than they wanted.

The research also showed women who accomplish their fertility desires are happier than women who have more or fewer children than they desire. Although “excess” births have a larger unhappiness effect than “missing” births individually, Canadian women lose more aggregate life satisfaction from “missing” than from “excess” births, because “missing” births are almost four times as common. In short, “missing” births are a larger social problem.