What does a baseline measure allow researchers to do?

What does a baseline measure allow researchers to do?

• A. It ensures random allocation.
• B. It allows comparisons to be made between conditions.
• C. It eliminates all extraneous variables.
• D. It measures external validity.

Answer: (B)

Baseline measures establish a starting point for each participant before any manipulation, so researchers can see how much change the intervention produces by comparing post‑manipulation outcomes to that starting level. This provides a reference that lets us compare what happened across different conditions, because any initial differences are accounted for when looking at how scores move from baseline. It doesn’t by itself ensure random allocation, eliminate all extraneous variables, or address external validity; random allocation is about how groups are formed, extraneous variables can never be completely removed, and external validity concerns generalizability of findings.

Baseline measures establish a starting point for each participant before any manipulation, so researchers can see how much change the intervention produces by comparing post‑manipulation outcomes to that starting level. This provides a reference that lets us compare what happened across different conditions, because any initial differences are accounted for when looking at how scores move from baseline. It doesn’t by itself ensure random allocation, eliminate all extraneous variables, or address external validity; random allocation is about how groups are formed, extraneous variables can never be completely removed, and external validity concerns generalizability of findings.