It's very hard to measure exactly how large it is, because there aren't good pre-existing metrics for it. You can measure in time (e.g., how far behind open weight models are from the best frontier models commercially available), but it's plausible that what seems like a relatively small time advantage (months) might mask a considerable difference in internal research sophistication. What we've seen repeatedly is simply that there does seem to exist a durable advantage in research productivity, at least for now.