Union success in representation elections: Why does unit size matter?

The author documents four facts regarding the pattern of NLRB-supervised representation election activity over the period 1952-98: (1) election activity fell sharply and discontinuously beginning in the mid-1970s, after increasing for two decades; (2) unions' election win rate declined less sharply, though continuously, over the entire period; (3) a 'size gap' characterized unions' win rate throughout the period, with a lower win rate in large units than in small ones; and (4) the size gap widened substantially between 1958 and 1998. A simple optimizing model of the union decision to hold a representation election can explain the first three facts. The author describes two possible explanations for the fourth fact, one based on differing behavior by employers in different size classes, and one purely statistical. Results of empirical tests using NLRB election data for 1952-98 suggest that those two explanations together can largely account for the observed patterns. (Author's abstract.)