Summary of exposure and outcome measures in studies using ecological measures to assess population-level effects of ART on HIV transmission.

↑, upward trend; ↓, downward trend; →, stable rate. For studies using two exposure or outcome measures, two arrows are shown, corresponding to the measures listed first and second.HAART, highly active ART; STD, sexually transmitted disease; VCT, voluntary counseling and testing; VL, viral load.