Conventional wisdom suggests large, persistent gaps between partisans' stores of political knowledge, fanning concerns about democratic accountability. We reconsider the frequency and size of these "partisan knowledge gaps," assembling a dataset of 162,083 responses to 187 items on 47 surveys. We find these gaps are smaller and less frequent than commonly understood; the average is a mere six and a half percentage points and gaps' "signs" run counter to expectations roughly 30% of the time. Additionally, while most question features fail to predict gap size, we find that questions featuring vague response options allow individuals to interpret potential answers through their own biases, inflating gaps' magnitudes. Our findings suggest that knowledge gaps — when they do exist — stem more from motivated responding than genuine differences in factual knowledge.