Scientific Journal Articles

I selected key scientific and medical journals for the period 1984–1986 using the Science Citation Index Journal Citation Reports ,^[9] which rank journals annually based on the number of citations to the articles they publish. Three highly prominent general science journals (Science, Nature , and the Proceedings of the National Academy of Sciences ) and two highly prominent medical journals (the New England Journal of Medicine and Lancet ) ranked within the top ten for all three years.^[10] Two other prominent medical journals (the Annals of Internal Medicine and Journal of the American Medical Association ) ranked only within the top fifty but ranked near the top of the subset of journals designated as "Medicine, General and Internal";^[11] moreover, these journals account for a high percentage of publications specifically about AIDS, according to several studies.^[12] Therefore, I selected these seven publications for the content analysis.

Next, I identified all articles published in these journals in 1984, 1985, or 1986 that cited Gallo's paper, using the 1984–1987 issues of the Science Citation Index .^[13] I retrieved and photocopied the selected articles and then screened them for "meatiness" using an algorithm developed for this purpose by Garfield.^[14] This algorithm selects for communications (articles, letters, and so on) reporting substantive research while eliminating items likely to have minimal impact. Items failing to achieve the threshold level identified by Garfield (such as short letters) I excluded from consideration. This yielded a total population of 244 articles, which I included in the content analysis.^[15]

I then coded each article for three pieces of information:

1. In the sentence containing the citation of Gallo's article,^[16] what kind of causal claim is made?

Explicit unqualified reference to the virus as the cause (These include, for example, "The cause of AIDS has been found to be HTLV-III"; "HIV, the virus that causes AIDS …"; "HIV is the primary etiological agent in AIDS"; and so on.)

Implicit unqualified reference to the virus as the cause (The virus is referred to as "the AIDS virus.")

Qualified reference to the virus as the cause (These include "HIV, the putative agent in AIDS …"; "HIV is believed to cause AIDS"; "The bulk of the evidence suggests [or strongly suggests] that AIDS is caused by HTLV-III"; or the use of words such as "etiologically linked," "associated," and so on.)

Implicit reference to the possibility that the virus may not be the cause (I included this coding possibility for the sake of logical completeness, but no articles were coded as such; therefore I excluded it in my subsequent analysis.)

Explicit reference to the possibility that the virus may not be the cause (These include references to the lack of evidence, to other hypotheses, to the need for cofactors, and so on.)

Article not cited in conjunction with a causal claim (Some authors cited the Gallo paper simply to establish a different point about HTLV-III.)

2. Are any of the thirteen coauthors of the Gallo article included among the coauthors of the article in question?^[17]

3. Are additional articles cited to support the causal claim? (Here I distinguished between articles that cited only Gallo or that cited Gallo along with earlier or roughly concurrent articles [1983 and 1984] by the Gallo, Montagnier, or Levy groups and those articles that also cited subsequent articles by any authors [1985 and 1986].)

I then tabulated data by journal. However, due to the small numbers, I have reported results only for the full population (the seven journals combined).^[18]