Editor retention

I've been playing with the changeset data for OpenStreetMap and looking to see what patterns I can find in the usage of various editors since changesets were introduced in the API 0.6 migration. We can start off just looking at the major editors by distinct users, i.e: everyone's favourite popularity contest.

If we look at the number of changesets by editor ordered by the number of distinct users, we get a pretty blindingly obvious result:

Editor Nc Nb Nu
Potlatch 988916 739623 55941
JOSM 1092702 1043776 12945
Merkaartor 124756 117812 2100
Mapzen POI Collector 1374 1341 239
BigTinCan Upload Script 266 219 124
iLOE 1113 1019 105
osm2go 901 868 99
Osmose Raw Editor 756 358 82
Mapzen Beta 218 155 65
bulk_upload 60110 55417 61
Table of raw data of editor usage, showing: Nc the number of changesets, Nb the number of changesets with bounding boxes, Nu the number of distinct users.

Where Nc is the number of changesets, total. Nb is the number of changesets with bounding boxes, which usually means they represent real, geographic edits. Nu is the number of distinct users. That's not exactly a massive shock - Potlatch has the most users because it's the editor on the OSM home page which requires the least effort to access. JOSM, somewhat surprisingly, has more changesets total and with bboxes, but maybe that's just because until recently every upload was it's own changeset. Merkaartor makes up the last of the "big three" editors with a couple of orders of magnitude more edits than than 4th place Mapzen POI collector.

Well, that didn't tell us anything we didn't already know. But how do editors compare at retaining their users? The following graph shows the number of users, logscale, against the length of time they've been editing over the past 6 months.

Editor retention over the period of 6 months.

What does this tell us? Not a great deal — due to the growth of the OSM community there is always going to be a large number of users up-front and it's not necessarily fair to assume they're in the 1 month category, because they only joined a month ago. Correcting for this and normalising the results between the editors brings out the data much better:

Normalised editor retention over the period of 6 months.

Here we can see that they all show the same basic pattern — a user is most likely to use the editor for less than a month and then lose interest. Given that the same pattern is visible in all three editors it's hard to say whether the editor itself has much effect on that, or whether these users just lose interest in OSM altogether. The most striking difference is that a significantly smaller number of users continue to use Potlatch and Merkaartor after the first month (33% and 39% respectively) than JOSM (64%).

Of course, this admits many explanations — it could be that JOSM is an editor which attracts users after the initial drop-out stage, or it could be an editor which persuades people not to drop out. The data could be made to support either...


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