ermisch and francesconi find that less than onefifth of cohabitations survive more than five years cohabitation before marriage has also been argued to raise the risk of divorce although the increased risk is small compared to other factors such as age at first marriage berrington and diamond there is also some evidence that there is negative selection in having a child outside of marriage ermisch however goodman and greaves find that while children in the united kingdom do better on average at ages three and five if born to married parents when controls for differences in other observed characteristics are conducted these differences disappear this they suggest implies that those children whose parents married in response to financial incentives saw no gain in educational outcomes