In reply to Luca Fracassi.

open data doesn’t impact development resources as it would just be a dump and people could just take a stab at it

This isn't really true. Anonymizing, cleaning, and collecting data is a huge amount of effort at this scale which is why it would be a distraction from the main focuses.

Dumping data indiscriminately is a good way to accidentally release private information.

like to know what are the current tools available for data driven decisions

WordPress.com has a lot Calypso instrumented with event tracking (called "Tracks"). See recordTracksEvent on github. If there are things that are not instrumented, they are just a PR away from being added.

It's not perfect because it is not wp-admin, but for the main focuses it is a pretty good proxy and has data for millions of users which is not something any new telemetry system would be likely to have for years (if ever given the differences of opt-in vs not).

Analyzing the data is also not zero effort, and I tend to find that having a hypothesis about what you are trying to learn from the data is a good prerequisite to actually going to look at the data.

Data tracking can also only take us so far and (as some others have noted) we can't let it completely drive all decisions. It's a feedback mechanism, but it's not the only one. More user interviews for instance would be good to see.