Error rate (%) per week - Trend over time.

*Wilson 95% confidence interval for the error rate.#Error rate(%) for three interviews using the tablet. Error rate(%) for four interviews using the PDA.**p-value for the test of proportions comparing the error rates for the first and third week of the study.***p-value, mixed effect model adjusting for the clustering effects for ‘fieldworker’ and ‘order’ in which the interviews were conducted.