{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T01:22:46Z","timestamp":1777598566205,"version":"3.51.4"},"reference-count":26,"publisher":"SAGE Publications","issue":"5","license":[{"start":{"date-parts":[[2011,10,1]],"date-time":"2011-10-01T00:00:00Z","timestamp":1317427200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Eval Rev"],"published-print":{"date-parts":[[2011,10]]},"abstract":"<jats:p>A mathematical model of HIV\/sexually transmitted infections (STI) transmission was used to examine how linearity or nonlinearity in the relationship between the number of unprotected sex acts (or the number of sex partners) and the risk of acquiring HIV or a highly infectious STI (such as gonorrhea or chlamydia) affects the utility of sexual behavior change measures as indicators of the effectiveness of HIV\/STI risk-reduction interventions. Findings indicate that the risk of acquiring HIV through vaginal intercourse is essentially a linear function of the number of unprotected sex acts and is nearly independent of the number of sex partners. Consequently, the number of unprotected sex acts is an excellent marker for the risk of acquiring HIV through vaginal intercourse, whereas the number of sex partners is largely uninformative. In general, the number of unprotected sex acts is not an adequate marker for the risk of acquiring a highly infectious STI due to the highly nonlinear per act transmission dynamics of these STIs. The number of sex partners is a reasonable indicator of STI risk only under highly circumscribed conditions. A theoretical explanation for this pattern of results is provided. The contrasting extent to which HIV and highly infectious STIs deviate from the linearity assumption that underlies sexual behavior outcome measures has important implications for the use of these measures to assess the effectiveness of HIV\/STI risk-reduction interventions.<\/jats:p>","DOI":"10.1177\/0193841x11432196","type":"journal-article","created":{"date-parts":[[2011,12,27]],"date-time":"2011-12-27T21:14:54Z","timestamp":1325020494000},"page":"550-565","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":5,"title":["Linearity and Nonlinearity in HIV\/STI Transmission"],"prefix":"10.1177","volume":"35","author":[{"given":"Steven D.","family":"Pinkerton","sequence":"first","affiliation":[{"name":"Department of Psychiatry and Behavioral Medicine, Center for AIDS Intervention Research, Medical College of Wisconsin, Milwaukee, WI, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Harrell W.","family":"Chesson","sequence":"additional","affiliation":[{"name":"Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Richard A.","family":"Crosby","sequence":"additional","affiliation":[{"name":"College of Public Health, University of Kentucky, Lexington, KY, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peter M.","family":"Layde","sequence":"additional","affiliation":[{"name":"Department of Emergency Medicine, Medical College of Wisconsin, Milwaukee, WI, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"179","published-online":{"date-parts":[[2011,12,27]]},"reference":[{"key":"bibr1-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1136\/sti.76.4.248"},{"key":"bibr2-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1056\/NEJM199208133270711"},{"key":"bibr3-0193841X11432196","unstructured":"CDC (Centers for Disease Control and Prevention). 2006. Sexually Transmitted Disease Surveillance, 2005, 1\u2013186. Atlanta, GA: U.S. Department of Health and Human Services."},{"key":"bibr4-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1016\/S1047-2797(99)00053-8"},{"key":"bibr5-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.2105\/AJPH.86.8_Pt_1.1075"},{"key":"bibr6-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1097\/00007435-199704000-00002"},{"key":"bibr7-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1136\/sti.2008.029850"},{"key":"bibr8-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1093\/oxfordjournals.aje.a121125"},{"key":"bibr9-0193841X11432196","first-page":"S27","volume":"14","author":"Holtgrave D. R.","year":"2000","journal-title":"AIDS"},{"key":"bibr10-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.7326\/0003-4819-128-4-199802150-00012"},{"key":"bibr11-0193841X11432196","unstructured":"Katz R. P., Caine V. A., Jones R. B.1990. Estimates of Transmission Probabilities for Chlamydial Infection. Chlamydial Infections: Proceeds of the Seventh International Symposium on Human Chlamydial Infections. New York: Cambridge University Press, 567\u201370."},{"key":"bibr12-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1097\/00002030-199601001-00011"},{"key":"bibr13-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1001\/jama.291.18.2229"},{"key":"bibr14-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1126\/science.280.5371.1889"},{"key":"bibr15-0193841X11432196","doi-asserted-by":"crossref","first-page":"S21","DOI":"10.1097\/00002030-199703110-00001","volume":"11","author":"NIMH Multisite HIV Prevention Trial","year":"1997","journal-title":"AIDS"},{"key":"bibr16-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1097\/00002030-199509050-00010"},{"key":"bibr17-0193841X11432196","first-page":"3","volume":"9","author":"Odets W.","year":"1994","journal-title":"AIDS & Public Policy Journal"},{"key":"bibr18-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1097\/00007435-200009000-00004"},{"key":"bibr19-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1177\/0193841X9301700503"},{"key":"bibr20-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1097\/00042560-199612150-00009"},{"key":"bibr21-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1097\/00126334-200209010-00010"},{"key":"bibr22-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1258\/095646203321605521"},{"key":"bibr23-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1097\/00007435-200205000-00009"},{"key":"bibr24-0193841X11432196","doi-asserted-by":"publisher","DOI":"10.1056\/NEJM199704103361507"},{"key":"bibr25-0193841X11432196","first-page":"S115","volume":"14","author":"Stephenson J. M.","year":"2000","journal-title":"AIDS"},{"key":"bibr26-0193841X11432196","first-page":"203","volume-title":"In Barrier Contraceptives: Current Status and Future Prospects","author":"Stone K. M.","year":"1994"}],"container-title":["Evaluation Review"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/0193841X11432196","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/full-xml\/10.1177\/0193841X11432196","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/0193841X11432196","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T20:45:53Z","timestamp":1777409153000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/10.1177\/0193841X11432196"}},"subtitle":["Implications for the Evaluation of Sexual Risk Reduction Interventions"],"short-title":[],"issued":{"date-parts":[[2011,10]]},"references-count":26,"journal-issue":{"issue":"5","published-print":{"date-parts":[[2011,10]]}},"alternative-id":["10.1177\/0193841X11432196"],"URL":"https:\/\/doi.org\/10.1177\/0193841x11432196","relation":{},"ISSN":["0193-841X","1552-3926"],"issn-type":[{"value":"0193-841X","type":"print"},{"value":"1552-3926","type":"electronic"}],"subject":[],"published":{"date-parts":[[2011,10]]}}}