Thanks Martin!
I'm not totally sure I understand your question, but I think you're asking how something can have just, say, 1 wikipedia citation and still be in the 90th percentile or whatever?
If so, I agree: that's confusing. But it is (if we've done our job correctly) accurate, since we're counting relative and not absolute performance.
Our sample of All Teh Articles (as randomly gathered from Web of Science) indicates that even a single Wikipedia citation puts you above ~90% of the articles out there. So then boom, you're in the ~90th percentile, despite a low raw count.
This is, alas, a bit counterintuitive, but there's no getting around it as long we have metrics where most articles score a big fat zero. This may eventually improve for some metrics; I expect the percentage of tweeted articles to grow in the coming years, for example. In other cases, like F1000, the sources are always going to be selective and we're just going to have to get use to sparse data.
The worst part is that often a single event doesn't mean much--a tweet, for example. Even though it puts you in the 90th percentile or whatever, it could be from your mom (or more often, from you). In these cases, the content will be much more important than the percentile; if it's a doctor tweeting your study to her patients, that one tweet can support an important story to your funders. In other cases, a single event means a lot more--like F1000. Finally others, like Wikipedia will be in between.
I think an important challenge for ImpactStory will be to do a better job of finding and presenting the content behind the numbers, to better unearth the good stories behind low counts. We'll be putting a lot of work into that in the coming months. In the meantime, reporting the raw numbers along with the percentiles at least gives folks more context than they had before.
j
a pretty good accomplishment, since fewer than 10% of articles attract one. That means you're in the 90th percentile (or thereabouts, depending on the year), surprising as it might be.