Table 1. Univariate correlations between article attributes and number of citations.
Citations were log transformed and count variables were square root transformed. Pearson correlations were used for numeric variables and polyserial correlations for binary and categorical variables.
| Attribute | Variable name | Correlation |
|---|---|---|
| How many citations did the study receive? | nCitedBy.log | 1.00 |
| What was the impact factor of the journal that published the study? | journal.impact.factor.tr | 0.45 |
| How many citations had been made from PMC to the last author’s previous papers? | last.author.num.prev.pmc.cites.tr | 0.30 |
| How many articles did the journal publish in 2008? | journal.num.articles.2008.tr | 0.25 |
| How many years had elapsed since the last author published his/her first paper? | last.author.year.first.pub.ago.tr | 0.24 |
| What was the mean citation score of the corresponding author’s institution? | institution.mean.norm.citation.score | 0.24 |
| How many citations had been made from PMC to the first author’s previous papers? | first.author.num.prev.pmc.cites.tr | 0.24 |
| How many of the journal’s studies were identified as having created microarray data? | journal.microarray.creating.count.tr | 0.23 |
| How many years had elapsed since the first author published his/her first paper? | first.author.year.first.pub.ago.tr | 0.22 |
| Was the corresponding author’s address in the USA? | country.usa | 0.18 |
| How many authors did the study have? | num.authors.tr | 0.17 |
| Was the study published in a journal considered a core clinical journal by MEDLINE? | pubmed.is.core.clinical.journal | 0.17 |
| How many previous papers had the last author published? | last.author.num.prev.pubs.tr | 0.15 |
| Did the study involve human subjects? | pubmed.is.humans | 0.08 |
| Was the study funded by the NIH? | pubmed.is.funded.nih | 0.07 |
| Was the study funded by an R-grant from the NIH? | has.R.funding | 0.07 |
| Did the study involve plants? | pubmed.is.plants | 0.07 |
| How many previous papers had the first author published? | first.author.num.prev.pubs.tr | 0.06 |
| Did the study involve cancer? | pubmed.is.cancer | 0.06 |
| How many cumulative years of NIH funding did the study receive? | nih.cumulative. years.tr | 0.03 |
| Was the corresponding author’s address in the UK? | country.uk | 0.03 |
| How many NIH grants did the study receive? | num.grants.via.nih.tr | 0.02 |
| What was the sum of the annual grants received from the NIH? | nih.sum.avg.dollars.tr | 0.01 |
| Did the study involve bacteria? | pubmed.is.bacteria | 0.01 |
| Was an associated dataset found in GEO or ArrayExpress? | dataset.in.geo.or.ae | 0.01 |
| How many of the last author’s previous papers were identified as creating gene expression microarray data? |
last.author.num.prev.microarray.creations.tr | 0.01 |
| Did the study use cultured cells? | pubmed.is.cultured.cells | −0.01 |
| How many of the first author’s previous papers were identified as creating gene expression microarray data? |
first.author.num.prev.microarray.creations.tr | −0.01 |
| Was this study listed as one that had reused data from GEO? | pubmed.is.geo.reuse | −0.01 |
| Was the corresponding author’s institution a government institution? | institution.is.govnt | −0.01 |
| Was the corresponding author’s address in Australia? | country.australia | −0.02 |
| Did the study receive interamural NIH funding? | pubmed.is.funded.nih.intramural | −0.03 |
| Was the corresponding author’s address in Canada? | country.canada | −0.05 |
| What is the rank of the corresponding author’s institution? | institution.rank | −0.06 |
| Was the last author female? | last.author.female | −0.07 |
| Was the first author female? | first.author.female | −0.08 |
| Was the corresponding author’s address in Japan? | country.japan | −0.10 |
| Did the study involve animals? | pubmed.is.animals | −0.11 |
| Was the corresponding author’s address in China? | country.china | −0.19 |
| Was the corresponding author’s address in Korea? | country.korea | −0.26 |
| Was the journal that published the study considered an open access journal? | pubmed.is.open.access | −0.30 |
| What year was the study published? | pubmed.year.published | −0.58 |
| What date was the study published? | pubmed.date.in.pubmed | −0.59 |