Your team replaced a chain-of-thought prompt with a four-stage pipeline and accuracy went down. What do you look at first?

When a pipeline change degrades performance, you must isolate the failure point. Check if each stage is producing valid output and whether the correct candidate is being filtered out prematurely. It is also critical to consider the noise band; on smaller evaluation sets, a minor drop in accuracy may be within the standard error and not indicative of a structural failure in the new design.