ABSTRACT
It turned out that George and I were not done with this topic yet. The impetus was partly legal. In our previous work (papers #3 and 11 in this volume), we had categorized employees as being either over 40 or under 40. But legally, that is not the whole story. Suppose an employer replaces employees in their 60s with others in their 40s. Both are in the protected class. Hence on the basis of our previous work, the 60s have a valid claim, because they are over 40 and they were replaced, in this hypothetical, because of their age. Thus, to be most helpful to the court, age, as well as time, should be treated as a continuous variable.
