An eight-state union history model with a transient phase after sexual debut and marriage

A joint eight-state continuous-time Markov model with a transient phase after sexual debut and marriage fits union histories well across four countries, quantifying early marriage spikes.

• Why it matters: Separate estimation from retrospective debut/marriage ages and current marital state can yield inconsistent inputs for demographic and sexually transmitted infection models.
• What they did: Using Demographic and Health Survey data from four countries (one to six rounds each), the authors fit a joint-model of eight-state competing continuous time Markov chain and reparameterize log hazards with transient phases after debut and after marriage.
• The result: In the first years after debut, marriage rates are 1.7 (95% CI 1.0–2.9) times later in Sierra Leone and 5.1 (95% CI 4.7–5.5) times in Rwanda, with elevated rates lasting 1.2 (95% CI 0.1–15.2) years in Sierra Leone to 3.5 (95% CI 2.3–5.2) years in Malawi.