Compare research sources in an evidence matrix

Compare the supplied sources to answer this question:
Which onboarding format appears more useful for first-time users of a reporting tool?

Comparison dimensions:
Intervention; outcome measured; timing; participants; main finding; limitations.

Sources with stable labels, dates, and excerpts:
Illustrative input notes only:
Source A, study memo, 2026-06, section Results: 12 new users tried a guided tour; 9 completed setup in the session. No control group or later retention measurement.
Source B, study memo, 2026-07, section Results: 10 new users used a checklist; 7 completed setup within one day. No control group; recruited from a different customer segment.

Create a Markdown matrix with one source per row and the comparison dimensions as columns. Add columns for the source's scope or population, evidence type, and stated limitations. Keep cells concise and attach the source label plus a page, section, or excerpt identifier to every substantive claim. If a dimension is not covered, write "not addressed" rather than inferring a position.

After the matrix:
- Identify the strongest areas of agreement and the exact points of disagreement.
- For each apparent conflict, check whether dates, definitions, populations, methods, or outcome measures could explain it. Distinguish a genuine contradiction from sources answering different questions.
- State what the available evidence supports for the research question, what remains uncertain, and the next source or measurement that would most reduce that uncertainty.

Use only the supplied material unless browsing is explicitly available and requested; do not fabricate references or imply that an excerpt represents a whole document. Preserve units and denominators when comparing numbers. Do not rank credibility solely by writing style, publication prestige, or agreement with a preferred conclusion.