"Each paper was assigned the IF of the journal in which it was published and the citations it received during two years following its publication year, and the r squared between the two series of variables was calculated for each year" - why would this figure change across time? "A journal’s IF was (and still is) based on its individual papers’ citation rates, and the citation rate of any individual paper was affected by its journal’s circulation and availability, which depended on its IF. Now the former is still true, but if new practices of literature search and usage limit the effect of journal IF on paper citation rates, the correlation between paper citation rate and IF should be decreasing over time" - aarontay

This makes total sense to me - the argument is that previously articles that were discovered and cited were likely to be published in prominent journals, but now the discovery is decoupled from the journal brand, the link between "important paper" and "important journal" is weakening. - barbara fister

That, and I think they're also showing that IF was never a terribly good proxy for "important paper." There's been some work just on that; super-high-impact individual papers often don't get published in high-IF journals, in part because they tend to challenge prevailing orthodoxy. - RepoRat

Hmm I think I am getting confused. Even if papers that eventually got a lot of cites were published in a low IF journal, that would just push up the IF of that journal wouldn't it? - aarontay

But maybe not enough to matter. - Meg V. Meg

And maybe the claim that this is an actual pattern is getting harder to see because the link is more random than ever. - barbara fister

And even if it does push up the IF, the question then is "who cares?" It's still not at all clear that the entire journal is more worthwhile, just that an article published in it got attention. - barbara fister

I do agree it makes no sense to look at where people publish to decide if they are doing well since papers published in same journal will have vastly varying citation rates, but it seems to me the correlation between IF of journals and the citation rates of papers published in them should not vary. At first I thought it was because they excluded papers not cited at all, but they stated clearly even including that would not affect the results... I can see if they did a subset of papers say top 10% of cited papers, but they did all papers.... Oh well my intuition must be wrong here. - aarontay

Remember that IF is calculated on a rolling set of papers. (It's what, three years' worth?) So yeah, rates are gonna vary, even for the same journal, because it's *not* the same set of papers over time, not even a built-up set. - RepoRat

It can help a scientist's career to be published in science or nature or cell or whatnot, because they set the bar high with a 90% rejection rate. Some think that if you can get it into nature, it must be an important article. - OMG 404 Joe

Ah okay. IF 2011 is based on citations in papers published in 2011 to papers published in the journal in 2010 and 2009. In the study they recalculated their own IFs and made a few changes but it's basically that. But the times cited for each paper is based on 2 years after publication. There is a difference. Though i wonder for a paper published in 2009, do they take the IF of the journal in 2009 or 2011 to compare? - aarontay

yes, what repo and Barbara say. there is a 2 year and a 5 year impact factor-- calculated only on articles in journals published in the previous 2 or 5 years respectively. so additional citations to an article published more than 2 or 5 years ago will not affect the impact factor. Barbara is spot on about the decoupling of prominent articles from the journal brand. I've been teaching for several years to faculty that a metric for journal quality is not necessarily reflective of article quality-- this just underscores that. - LibrarianOnTheLoose from BuddyFeed

Well yes, but in the study the citation rate they calculate to compare against IF is also 2 year window..... So this study isn't quite about how some papers might be late bloomers. - aarontay

[Confession: I actually don't understand the math behind IF so a lot of this study was blah blah blah blah to me.] - barbara fister

This does a good job of explaining it... http://blogs.law.harvard.edu/pamphle... "At one point, roughly up through World War II, the numbers were in the 70s and 80s. Three quarters of the top-cited papers were not in the top IF journals. After the war, a steady consolidation of journal brands, along with the invention of the formal Impact Factor in the 60s and its increased use, led to a steady decline in the percentage of top articles in non-top journals. Basically, a journal’s imprimatur — and its IF along with it — became a better and better indicator of the quality of the articles it published. (Better, but still not particularly good.)" But, that changed in the 1990s... - OMG 404 Joe