Read the methods section to classify how participants were allocated, what the comparator was, and when outcomes were measured, then record the design label with the sentences that justify it. That one-line classification fixes which appraisal tool you apply next.
Work through the methods in order
- Find the allocation statement. Look for how participants entered the study: randomization to groups, allocation by a non-random rule, or a single group followed over time. The sentence naming the mechanism is your first design signal.
- Identify the comparator. Note whether the trial compares an intervention against a control, placebo, usual care, or another active treatment, and whether groups run in parallel or participants cross over. This separates parallel-group from crossover designs.
- Fix the outcome timing. Record when outcomes were measured relative to the intervention, since a single post-intervention measurement and repeated follow-up describe different structures.
- Write the label with quoted evidence. Produce one line such as "parallel-group randomized trial" followed by the exact sentences on allocation, comparator, and timing that support it. Keep the quotes verbatim so a co-author can check the classification.
Why the label comes first
The NHLBI quality assessment tools are design-specific: each tool focuses reviewers on internal validity and potential flaws in study methods or implementation, and users define their own judgement parameters. Selecting the tool before you know the design risks applying criteria that do not match the study.
For a randomized trial, the Cochrane Handbook's RoB 2 assesses a specific randomized-trial result across bias domains using signalling questions and written justifications, producing low risk, some concerns, or high risk judgements. That structure fits a result you have already classified as randomized.
CONSORT 2025 is a reporting guideline and checklist for randomized trials; it supports complete reporting and is not a study design or quality appraisal tool. Use it to check whether the methods report the details your classification depends on, then apply the appraisal tool that matches the design.
Boundary to watch
If the methods do not state an allocation mechanism, the design remains unresolved. Mark the classification as pending and note which sentence is missing before you choose an appraisal tool.