Table 1

Comparison of Several Methods of Evaluating a Medical Intervention

Method

Strengths

Weaknesses


Randomized controlled trial

1.

No temporal bias

1.

Cost and effort

2.

No selection bias

2.

Recruitment


Observational cohort study

1.

No temporal bias

1.

Cost of data collection

2.

Selection bias if an

important risk factor is

omitted or not

adequately quantified


Paired availability design

1.

Lessens selection bias

1.

Assumptions in Table 2


Baker et al. BMC Medical Research Methodology 2001 1:9   doi:10.1186/1471-2288-1-9

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