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There is no validation team, however everyone can check the latest edits [1]. If there's a developed community in a location, say someone in your city, you can validate it yourself. Someone can use Notes feature [2] and report that the street has inaccurate information - by linking to some photo proof.

Thankfully many (not all, like POI) edits can be checked via satellite imagery [3], of which OSM has permission to use many - global ones being Bing, Maxar, Esri, Mapbox. With so much sources of imagery, the update rate is acceptable for most places.

All in all, the result is not as bad as you'd expect. From normal people I hear that OSM is "very accurate" (at least here in Europe). Oddly enough, nobody says anything about blatantly fake info, which indeed does very rarely slip, but apparently gets reverted.

Now as I am thinking, there is "validation team" of sorts, that's Mapbox data team, which uses OSMCha [4] to flag suspicious changesets and checks them (albeit not by physically going there).

[1] https://wiki.openstreetmap.org/wiki/Quality_assurance#Monito...

[2] https://wiki.openstreetmap.org/wiki/Notes

[3] https://wiki.openstreetmap.org/wiki/Aerial_imagery

[4] https://wiki.openstreetmap.org/wiki/OSMCha

In many regions any bogus data will be spotted fairly quickly. New mappers are monitored by the community and guided to documentation if necessary, and real abuse is dealt with (either by just reverting vandalism, or blocking the user outright via the Data Working Group).

Areas with local mappers will be watched even more closely.

All in all OSM often reaches a level of detail Google Maps can only dream of. In the Netherlands the number of outright errors is really quite small, and at least everything is pretty much up-to-date. Google Maps is still showing (and routing over) a trunk road in my home town that closed over a year ago.

> A map of the world seems like sooo much work to keep updated

It's really not that bad. Major infrastructure draws the attention of people who are fascinated by highways or railway tracks. The same goes for national cycling networks and the roads and cycleways these use. Major administrative rearrangements (changes in the borders of municipalities etc.) also draw a particular group. And finally, local mappers care about their local piece of map, often down to the newest projects. As a local mapper myself I find it a joy to be the first to map a new street or add a newly assigned name to some unnamed way.

It's also a nice hobby, because you visit parts of your town to survey you wouldn't ever come otherwise.

> I wonder how many contributors there are for OSM maps. I have personally never updated a map there and have been too lazy to read up on how to do that.

I was linked to OSMstats [1] earlier - was fun to look through, and the "Contributor to Elements Created" ratio made me proud to be a Canadian contributor :)

[1] https://osmstats.neis-one.org/?item=countries

The answer is crowd sourcing. Everything one person creates or modifies needs to be voted on by multiple people. After x votes and y percent in favour of the change it‘s visible to everyone. The x and y numbers could change depending on the user‘s reputation etc.

Think of it like the stack overflow „tasks“ you are asked to do all the time: review this question, do this, do that ...

Because of the OSM data model, changes can't be really held in "unaccepted" state. One would run into editing conflicts[1].

On Wikipedia withholding edits until review works in some language versions [2], but because Wikipedia pages are "atoms" that stand on their own, they have it easier.

[1] https://learnosm.org/en/josm/josm-conflict-resolution/

[2] https://en.wikipedia.org/wiki/Wikipedia:Flagged_revisions/Si...

This would not work, in nearly all cases there is not enough of mappers to handle this.

And anyway real problem is a stale data - especially shops. Data that was wrong from start is rare, OSM has nearly no vandalism.

Making easier to verify data is much better idea (one of nicely working things is a StreetComplete Android app - about 20% of shops where I am asked to add opening hours are gone, so I open a note, take a photo and later me or some other mapper removes no longer existing shops)