Pubmed RSS feed parsing out of order

I try subscribing to RSS feeds in Pubmed following this process: https://www.nlm.nih.gov/bsd/disted/pubmedtutorial/040_060.html.  I add the generated feed to Newsblur.  The results are out of order from the feed.  Interestingly, if I add “s” to the “http” feed url (thus, “https”), the results are different, but still incorrect.

To reproduce:

  1. Go to http://www.ncbi.nlm.nih.gov/pubmed/?term=diabetes
  2. Click on “Create RSS” and use default settings.
  3. Open the XML link and add to Newsblur.
  4. See the difference in order of publications listed in Pubmed and Newsblur.  For me, there appears to be a trend of chronological order, but it is not exact.
  5. Bonus: change the feed url to “https” and see how the results change.
    These types of RSS feeds worked for me last year, but recent feeds I have added had done what I’ve described above.
1 Like

Can I have the exact RSS url you’re using? You can right click on the feed title and go to Site Settings to find it.

Copied from Site Settings:

http://www.ncbi.nlm.nih.gov/entrez/eutils/erss.cgi?rss_guid=14czX-i9THTaCKgUr2pOdoINZPIE5HRKGtyrVoC1…

And the https: https://www.ncbi.nlm.nih.gov/entrez/eutils/erss.cgi?rss_guid=14czX-i9THTaCKgUr2pOdoINZPIE5HRKGtyrVoC…

Looks like the reason is that the feed does not contain dates, so NewsBlur sticks the fetch date in. But that means order does not get preserved. It’s just too difficult to do, since everything is sorted by the story date, and that would mean offsetting every subsequent story by 1 second in order to preserve order. It would be possible, but I’m not sure what the ramifications are.

As someone who subscribes to a lot of PubMed alerts, I can tell you that this only happens when the feed is initially added. Now on whenever there are new articles for ‘diabetes’, they will have the correct date.

ok, that’s reassuring.  Thanks, Samuel, for the explanation.  I will wait a bit for new articles to come to see how it works.