Social Democratic Party Annual Membership Figures
According to figures cited at the "First Convention" of March 6-9, 1900, the Social Democratic Party had added about 1000 dues paying members from the first of the year, to stand at a total of about 4,500 at the time of the Convention. [Social Democratic Herald, March 17, 1900, pg. 1]
1899
About 3,500
1900 About 4,500
Socialist Party of America Annual Membership Figures
The Socialist Party collected dues monthly rather than annually, using a system of membership cards and dues stamps. Under this system, stamps would be advanced in bulk to State Party organizations and Language Federations, who then sold these stamps to the membership at meetings. Members missing a previous meeting would generally buy more than one stamp at a time to pay for dues in arrears. Local and State organizations -- or Language Federations, as the case may be -- would get a share of the money for each dues stamp sold and would remit the balance of funds to the National Office.This system, borrowed from trade unions of earlier days, inevitably resulted in a fluctuation of the number of stamps sold by the National Office each month. The standard method of calculating the membership of such organizations involves the average number of stamps sold over the course of a particular quarter or year. Scholars should remain dubious of any single monthly stamp sales total being presented as indicative of a group's true membership size, as partisans of the day often did.
During the years 1901 and 1902, dues payments to the National Office from the various states were somewhat irregular in frequency and record-keeping seems to have been poor. The purported membership at the time of the 1901 Unity Convention of a round "10,000" is fanciful, although the party does seem to have approached this membership figure during the subesequent year. No hard numbers for 1902 membership are available, but the rough and round estimate may be regarded as approximately correct.
With the exception of the 1901 and 1902 estimates, which are based on material published in the Social Democratic Herald, and the figure for the first six months of 1903, which comes from Appeal to Reason no. 405 (Sept. 5, 1903), the following series of average monthly dues stamp sales per year is based upon the official statistics published annually in The American Labor Year Book by the Rand School of Social Science, a Socialist Party training school. The figures may be regarded as official and were not subject to any form of systemic falsification:
1901
("About 4,000 at the time of the Unity Convention -- SDH of May 25, 1912, pg. 4).
1902
- (no statistics kept: approximately 10,000 claimed in statement to party members.)
1903
15,975—— + 59.8%
1904
20,763 -- -- + 30.0%
1905
23,327—— + 12.3%
1906
26,784 ---- + 14.8%
1907
29,270——- + 9.3%
1908
41,751—— + 42.6%
1909
41,470 -——0.7%
1910
58,011—— + 39.9%
1911
84,716—— + 46.0%
1912
—— 118,045 --- -- + 39.3%
1913
95,957——18.7%
1914
93,579—— - 2.5%
1915
79,374——15.2%
1916
83,284—— + 4.9%
1917
80,379——- - 2.5%
1918
82,344—— + 2.4%
1919 (Q-1) 104,822
—— + 27.3%
From this a few things should be noted: (1) That the Socialist Party showed its most explosive period of growth in the years 1910-12; (2) That despite the defection of the party's Right Wing over the issue of the war, the SPA held its own in 1917-18 despite its uncompromising anti-militarist stance and the harsh government persecution related to this; (3) That the alleged "flooding" of the membership with new elements during the first quarter of 1919 was well within historical parameters of growth for the group both in terms of absolute number of members and the percentage rate of growth which the new recruits represented.
After the suspensions, expulsions, and defections ensuing from the party crisis of 1919 and its aftermath, Socialist Party membership plummeted. Figures below for the 4th quarter of 1919 and for 1920 are from Trachtenberg and Glassberg (eds.), The American Labor Year Book, 1921-1922, pg. 392; Figures for 1921-1922 from DeLeon and Fine (eds.), The American Labor Year Book, 1925, pg. 141:
1919 (Q-4)
34,926——66.7%
1920
26,766——23.4%
1921
13,484——49.6%
1922
11,019——18.3%