Bias parameters in behaviours between IDI and FTFI with female sex workers in the validation study (N=63), Iran, 2010–2011
| Risk behaviours | Bias parameters | |
|---|---|---|
| Categorical | Sensitivity (95% CI)* | Specificity (95% CI)† |
| Ever married | 92.0 (80.8 to 97.8) | 91.7 (61.5 to 99.8) |
| Ever used drugs | 90.2 (79.8 to 96.3) | 100.0 (15.8 to 100) |
| Not tested for HIV, last 12 months | 93.3 (77.9 to 99.2) | 84.8 (68.1 to 94.9) |
| Not receiving the result of the HIV test | 66.7 (22.3 to 95.7) | 100.0 (86.3 to 100) |
| History of genital ulcer or discharge, last 12 months | 63.9 (46.2 to 79.2) | 100.0 (87.2 to 100) |
| Non-condom use last sex act | 87.5 (67.6 to 97.3) | 91.7 (77.5 to 98.2) |
| Ever associated with a venue to sell sex | 52.4 (29.8 to 74.3) | 97.6 (87.1 to 99.9) |
| Numerical | Mean difference between IDI and FTFI (95% CI)‡ | Pearson correlation coefficient (95% CI)§ |
| Number of sexual contacts, last 7 days | 1.48 (0.7 to 2.3) | −0.2 (−0.4 to 0.1) |
| Number of non-condom use acts, last 7 days | 0.40 (0.0 to 0.7) | −0.2 (−0.5 to 0.1) |
| Age at first sex act for money, drugs or shelter | 0.05 (−1.1 to 1.2) | −0.5 (−0.7 to −0.3) |
| Number of clients, last 7 days | 0.80 (0.2 to 1.5) | −0.3 (−0.6 to −0.1) |
| Number of days in last week with sex with a client | 0.90 (0.2 to 1.5) | −0.4 (−0.6 to −0.1) |
| Income through last commercial sex act (US$) | 1.40 (−0.6 to 3.4) | −0.2 (−0.4 to 0.1) |
*Sensitivity is the conditional probability, p (classified as FSW having the risky behaviour for HIV|truly having the risky behaviour).
†Specificity is the conditional probability, p (classified as FSW without the risky behaviour for HIV|truly don't have the risky behaviour).
‡Positive mean difference represents under-reporting in FTFI.
§Pearson correlation coefficient between FTFI and the mean difference between IDI and FTFI.
FSW, female sex workers; FTFI, face-to-face interview; IDI, in-depth interview.