Adam Mosseri's recent post on engagement rates describes how Instagram's recommendation system evaluates content and how you should be evaluating your own performance.
The most important thing Mosseri said is also the most counterintuitive for anyone who has spent time staring at Instagram analytics dashboards: reach is not the metric you should be optimizing for because it’s a downstream consequence of engagement, not a lever you can pull directly.
When reach underperforms expectations, the tempting response is to look at distribution factors: posting time, hashtag strategy, the cadence of recent posts, or whether the algorithm is "suppressing" your content in whatever conspiratorial way the internet tends to assume platforms behave. But Mosseri is pointing directly at a more honest diagnosis: the algorithm distributes content in proportion to how people respond to it.
Engagement rate, defined as the percentage of viewers who took a specific action after seeing a post, is the signal the system treats as evidence of quality and relevance. High reach with low engagement doesn't compound—the algorithm reads it as a sign that the content was exposed to people who didn't find it interesting enough to act on, and adjusts accordingly. Low initial reach paired with high engagement, on the other hand, is the foundation for broader distribution, because it reads the strong engagement-to-view ratio as evidence that this content would likely interest a larger audience.
Mosseri also fleshed out the distinction between connected reach (followers who see a given post) and unconnected reach (non-followers who encounter it through algorithmic recommendation, Explore, Reels, or other discovery surfaces). For connected reach, Mosseri points to like rates as the more significant signal, meaning Instagram's algorithm determines feed placement based substantially on a follower's historical engagement with your account. For unconnected reach, shares emerge as the more powerful signal, as an act of personal curation and recommendation, which Instagram interprets as strong evidence that your content has value beyond its immediate audience.
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