3.A Sufficiency of Evidence (CLE-1.H)

Sufficiency is not a fixed amount. It is a relationship between how big a claim is and how much the evidence can actually cover. One sharp example can feel like plenty when the claim is narrow and the example sits right inside it. The same example feels like almost nothing when the claim tries to speak for a much larger group. A single quote from one teacher says a lot about that teacher and very little about every teacher in the district.

Quantity and quality trade against each other but do not replace each other. More evidence of a weak kind still produces a weak case, because the problem is not how many data points you have but what population or situation they were drawn from. Three friends who love night classes are a sample picked by friendship, not by anything connecting them to the thousands of students a college would need to convince itself about. Adding three more friends does not fix that, since the selection method is still the flaw. This is why sufficiency fails by adding more counts from the same interchange, same day, same kind of source: the gap is in kind, not in quantity.

This connects directly to how claims get scoped. When a claim narrows, from all teenagers down to students at one school, the evidence needed narrows too, and observations that once felt thin can suddenly feel ample because they now match the population exactly. Writers who understand this choose evidence to fit the claim's actual reach, then use commentary to explain why that fit holds, which is the move the next skill builds on.