Discrepancy between web portland and API?

[scott_chamberlain]

Hello, 

A user of the R client for the PLOS Solr API I maintain (rplos) reports that he gets different results searching the PLOS web portal vs. using the search API. 

In the web portal there are 761 results for this query: http://www.plosone.org/search/advanced?pageSize=15&sort=&queryField=everything&queryTerm=&unformattedQuery=%28subject%3Apsychology%29+AND+publication_date%3A%5B2010-01-01T00%3A00%3A00Z+TO+2010-12-31T23%3A59%3A59Z%5D&journalOpt=all&subjectCatOpt=all&filterArticleTypesOpt=all

Using the Solr API there are 6314 results: http://api.plos.org/search?q=(subject:psychology)%20AND%20publication_date:%5B2010-01-01T00:00:00Z%20TO%202010-12-31T23:59:59Z%5D&rows=0

Does the web portal use the Solr API directly?  Assuming the user wants to search papers in subject area psychology only, and for the above publication date range, which is the correct answer (761 or 6314, or neither)?  Was either query not specified correctly? 

Here's the issue on the rplos repo for reference: https://github.com/ropensci/rplos/issues/75

Thanks! Scott