An application of Systematic Anomalous Case Analysis to improve models predicting contraceptive use in the Philippines.

Amidst persistently high unintended pregnancy rates and lags in contraceptive use, novel methodological approaches may prove useful in investigating sexual and reproductive health outcomes in the Philippines. Systematic Anomalous Case Analysis (SACA) - a mixed-methods technique - was employed to examine predictors of women's lifetime contraceptive use. First, multivariable, longitudinal Poisson regression models predicted fertility and sexual debut using the 1998-2009 Cebu Longitudinal Health and Nutrition Surveys (CLHNS), then regression outliers and normative cases were used to identify 48 participants for in-depth interviews (2013-2014) for further examination. Qualitative findings from 24 women highlighted 'control over life circumstances' was critical, prompting the addition of two items to the original quantitative models predicting any contraceptive use (n=532). Each of the items, 'what happens to [them] is their own doing' and '[I] do not [have] enough control over direction life is taking [me]', significantly and independently predicted any contraceptive use (aOR: 2.37 (CI: 1.24-4.55) and aOR: 0.46 (CI: 0.28-0.77), respectively). The findings demonstrate the utility of SACA to improve the understanding and measurement of sexual and reproductive health outcomes and underscore the importance of integrating psychosocial constructs into existing models of fertility and reproductive behaviour in the Philippines to improve sexual and reproductive health outcomes.