Gordon Forbes, “Birth Order and Political Success: A Study of the 1970 Illinois General Elections,” Psychological Reports, 197 1, 29, 1239-1242.
The present study failed to find an overrepresentation of firstborns among political candidates. All candidates had either been nominated through contested primary elections or through the nominating procedures of their political party. As a consequence, they were individuals who had impressed either the electorate or political professionals with their ability and success. Nearly all of the available evidence suggests that firstborns should be greatly overrepresented in such a sample. The failure to find an overrepresentation of firstborns is one of only a few such failures reported in the literature. Even given the limitations imposed by the present sample, this failure strongly suggests that those factors which produce such a massive overrepresentation of firstborns in scientific and scholarly pursuits do not operate as selective factors in entrance into political life.
The finding that firstborns and lastborns were more likely to win their contests than middle-borns supported the original hypothesis. This indicates that while firstborns or lastborns are not overrepresented among political candidates, they are overrepresented among successful candidates. This suggests that some of the personality factors associated with different ordinal positions are selective factors in determining political success but are not selective factors in determining entrance into political life. Although the magnitude of the relationship between birth order and political success is rather small, when one considers the extraordinary complexity of the variables that produce political success or failure, the demonstration of any relationship between political success and birth order is most striking.