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Table 1 Mixed methods evaluation strategy, sample, goal, data collection timing, and analysis

From: Study protocol: a cluster randomized trial to evaluate the effectiveness and implementation of onsite GeneXpert testing at community health centers in Uganda (XPEL-TB)




Data collection


Process metrics

All patients referred for TB diagnostic evaluation at intervention sites

Examine variability in adoption of and fidelity to intervention components across sites

Entire post-randomization period

Multivariate regression models


1) Health workers involved in TB evaluation at all sites*

2) Sixty patients per site (20 patients/site, 400 total pre-randomization; 40 patients/site, 800 total post-randomization)**

Examine whether the XPEL TB strategy modifies targeted barriers to TB diagnostic evaluation

Once before and once after trial is completed

Multivariate regression models

Focus groups

Health workers involved in TB evaluation at intervention sites*

Assess acceptability of each component of the intervention strategy.

After trial is completed

Thematic interpretation

In-depth interviews

Purposive: 20–30 health workers at high- and low-performing intervention strategy sites (2–3/site)

Understand reasons for variability in adoption and implementation of the XPEL TB strategy

After trial is completed

Thematic interpretation

  1. *Based on prior experience, we anticipate 5–10 staff members will be involved in TB diagnostic services at each health center (50–100 each at intervention and control health centers)
  2. **Patients will be selected randomly within strata based on gender and timing of health center visit (undergoing TB testing vs. completed testing/initiating TB treatment)