Yeh these graphs are purely based on groups who were still active and took the survey in 2019, so they won’t include groups that existed in years pre-2019 and then stopped existing before 2019. We’ve changed the title of the graph to make this clearer.
That said, when we compare the pattern of growth across cohorts across surveys for the LGS, we see very similar patterns across years with closely overlapping lines. This is in contrast to the EA Surveys where we see consistently lower numbers within previous cohort across successive surveys, in line with attrition. This still wouldn’t capture groups which come into existence and then almost immediately go out of existence before they have chance to take a survey. But I think it suggests the pattern of strong growth up to and including 2015 and then plateau (of growth, not of numbers) is right.
Yeh these graphs are purely based on groups who were still active and took the survey in 2019, so they won’t include groups that existed in years pre-2019 and then stopped existing before 2019. We’ve changed the title of the graph to make this clearer.
That said, when we compare the pattern of growth across cohorts across surveys for the LGS, we see very similar patterns across years with closely overlapping lines. This is in contrast to the EA Surveys where we see consistently lower numbers within previous cohort across successive surveys, in line with attrition. This still wouldn’t capture groups which come into existence and then almost immediately go out of existence before they have chance to take a survey. But I think it suggests the pattern of strong growth up to and including 2015 and then plateau (of growth, not of numbers) is right.
Ah, great, that makes sense. Thank you for the clarification!