Define engagement before measuring it
I would not start by searching for one engagement number. I would first define what meaningful use looks like for this product and for the customer problem it is meant to solve. A user can click frequently without reaching value, while another user may need the product only occasionally and still depend on it.
I would write down the behavior that represents progress, the audience I am measuring, and the decision the metric should support. That keeps a product engagement score from becoming a decorative dashboard number.
Combine breadth, depth, and frequency carefully
I would look at three useful dimensions: breadth, or how much of the relevant product is used; depth, or whether the behavior reaches a meaningful level; and frequency, or how consistently the behavior occurs. I would choose definitions that fit the product rather than copying a formula from another business.
I would segment the result by customer type, lifecycle stage, plan, and meaningful use case. An average can hide a new user who is learning, a mature user who has found a stable workflow, or a customer who is active but not successful.
Turn the signal into a decision
I would pair the score with qualitative evidence, retention, support themes, and outcome measures. If engagement falls, I would ask which behavior changed and why before launching a feature. If it rises, I would still check whether customers are reaching the intended value.
My bottom line
I use an engagement score as a question generator, not a verdict. The Product HQ product manager certification can strengthen the judgment behind product measurement, and the Product HQ newsletter shares more practical guidance.