Draft lottery (1969)

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On December 1, 1969, the Selective Service System of the United States held a lottery to determine the order of draft (induction) into the U.S. Army.

Representative Alexander Pirnie (R-NY) drawing the first number. Congressman Pirnie's left hand appears to be on the mouth of the jar.

1 Method
2 Consequences
3 References
4 External links

[edit] Method

The days of the year, from 1 to 365, were written on slips of paper and the slips were placed in plastic capsules. The capsules were mixed in a shoebox and then dumped into a deep glass jar. Capsules were drawn from the jar one at a time.

The first number drawn was 257 (September 14), so all registrants with that birthday were assigned lottery number 1. Men of draft age (those born between 1944 and 1950) whose birthday fell on the corresponding day of the year would all be drafted at the same time. The highest draft number called from the 1969 lottery was number 267 (September 24).

1969 draft lottery scatterplot. A scatterplot of the days of the year (horizontal axis) and their ranks (vertical axis) shows a noticeable absence of days in December with high ranks (later induction).

A secondary lottery was also held on the same day, to construct a random permutation of the 26 letters of the alphabet. For men born on a given day, the order of induction was determined by the rank of the first letters of their last, first, and middle names. [1]

The lottery was conducted again in 1970 (for those born in 1951), 1971 (1952) and 1972 (1953), although the last lottery went unused as the draft itself was suspended in 1973.

[edit] Consequences

It was quickly noticed that draft ranks were not uniformly distributed over the year. In particular, birthdays in December had lower (earlier) draft ranks, on average, than birthdays in other months. This led to complaints that the lottery was not random as the legislation required. Analysis of the lottery method suggested that the procedure (mixing the capsules in the shoe box and dumping them into the jar) did not mix the capsules sufficiently, however the less than random lottery was allowed to stand. The lottery system was later modified to produce a more random result.

[edit] References

S.E. Fienberg. "Randomization and Social Affairs: The 1970 Draft Lottery". Science, volume 171, pages 255-261 (1971). (Cited by Starr as the "best and most comprehensive" article on the topic)
D.E. Rosenbaum. "Statisticians Charge Draft Lottery Was Not Random," New York Times, January 4, 1970, p. 66.
Selective Service System: History and Records [2]
Norton Starr. "Nonrandom Risk: The 1970 Draft Lottery". Journal of Statistics Education, volume 5, number 2 (1997). (Also available on-line: [3] Contains a lesson plan for statistics class using the 1970 and 1971 draft lottery data)