I think it depends on how you are measuring right?
Coming off of a year leave it wasn't until a couple months in that I felt ready to be integrated into our sprints. However during those couple months I was reviewing code and team practices and providing value by asking questions about things and understanding how things work. The outsider-looking-in portion of on-boarding brings immense value to a team in terms of identifying blind spots or ways that weren't considered initially if the on-boarding is done thoughtfully and intentionally.
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