Indicator 9.7.1: "Age-mixing in sexual partnerships (young women age 15-24, any partner in the last 12 months)"


Proportion of young women 15-24 who have had sex in the preceding 12 months with a partner who is 10 or more years older than themselves.

Measurement Tools

A nationally representative general population survey.

What It Measures

This indicator measures the proportion of young women having sex with older men.

Sex between young women and older men is often risky because young women lack the power in the relationship to negotiate safe sex. It is also an efficient means of spreading HIV infection, since, for physiological reasons, younger women are more likely to become infected. Each sexual act with an infected man carries a higher risk of infection for a young girl, and older men are more likely than younger men to be infected. AIDS prevention programmes sometimes try to address this issue through IEC campaigns aimed at making sex with younger women socially unacceptable among older men and through initiatives to increase girls’ negotiating power.

How to Measure It

In a general population survey respondents are first asked whether they have had sex in the preceding 12 months. Those who answer in the affirmative are asked whether any of their last three partners during this period were at least 10 years older than themselves. The numerator includes all respondents who answer that this was the case.

This indicator should be reported as separate percentages for the age groups 15–19, 20–24 and 15–24 years. If possible it should be further disaggregated by current marital status.

Strengths and Limitations

This measure has two major limitations, the first being that people often do not know the exact age of their sex partners. This is more likely to be true of casual partners than of spouses. The second is that the age difference constituting an elevated risk of exposure to HIV is not precisely known.

When uncertain about a partner’s age, respondents frequently give numbers clustering around numbers such as 20 or 30. This may well distort the indicator. It should be noted, however, that the biases introduced through age clustering or age misreporting are unlikely to change greatly over time, so this may be of little consequence when trends are being examined.

This measure cannot give an exact picture of patterns of age-mixing and cannot capture small shifts in the age gap between partners. Nevertheless, it should capture the substantial changes in age-mixing promoted by programmes on HIV prevention and life skills, since women are unlikely to mistake a peer for a man much older than themselves. If women increasingly choose to have sex with their peers rather than with older men, or if older men become less likely to seek out substantially younger partners, these changes will be reflected in the indicator, regardless of errors in age-reporting.