The current default timestamp on Wikipedia

The current default timestamp on Wikipedia

Wikipedia pages each have their own history with detailed information about every revision, and this public log is one of the core aspects of the project. However, unless you find and use the special “View history” tab, the only information on Wikipedia articles that directly tells you the time and nature of the last change is on the bottom of the page, in tiny font and in UTC time.

What we tested

The new timestamp we tested

The new timestamp we tested

We think that information about when an article was last changed should be far more transparent on Wikipedia. For one week, we tested a new feature for readers and editors that provided a more direct window into the editing process.

On a sample of around 20,000 English Wikipedia articles, we added a much more prominent timestamp. Its text was relative to the reader (e.g, “Last updated 5 minutes ago”) and linked directly to the full revision history. Whether visitors saw the new timestamps was randomly assigned based on an anonymous token.

The results

Click to enlarge

Comparison of the click-through rates for different user groups in the experiment.

We found that adding the timestamp link as a supplementary entry point nearly doubled (+96.2%) the overall number of impressions of article revision histories (whether from registered or unregistered users). The increase was particularly strong for anonymous editors and readers, who landed on the history page more than twice as often (+120.6%); for registered users, there was a smaller but still significant increase in article history views (+42%). This result was seen even when we controlled for repeat clicks on either link. The conclusions from this analysis are described in detail on the wiki page about our experiment. We released an anonymized dataset from this experiment under a Creative Commons Zero license and we will do so for all future experiments.

Prior to this experiment, there was little to no data available about how many readers were really aware of the history tab’s location and purpose. The results we’ve seen in this A/B test strongly suggest that many people are interested in the history of Wikipedia articles they are reading, and that giving information about the last edit encouraged more people to take a closer look at the editing record.

What’s next

This is a relatively small change in the Wikipedia interface, but we’re extremely excited to see interest in deeper engagement with the encyclopedia among readers. Future iterations of this experiment may involve transforming this timestamp into a more direct call to edit articles that are severely outdated, though clearly the point at which an article becomes out of date is somewhat subjective. In the short term, we’ll be moving on to other experiments, though it is always possible that community members on Wikipedia may want to implement this feature permanently.

While our experimental features group is primarily interested in ways to engage editors, we did not try to correlate any increase in editing activity with the appearance of the timestamp, since any impact would be indirect and minor at best. If you’re interested in learning about feature experiments we plan to test in the near future, check out our documentation on Wikipedia.

Steven Walling, Community Organizer
on behalf of the Editor Engagement Experiments team

2012-07-09: Edited to expand the “results” section with more detail and a plot, and to include a link to the now published dataset