  In this study, we address the question whether (and to what extent,
respectively) altmetrics are related to the scientific quality of papers (as
measured by peer assessments). Only a few studies have previously investigated
the relationship between altmetrics and assessments by peers. In the first
step, we analyse the underlying dimensions of measurement for traditional
metrics (citation counts) and altmetrics - by using principal component
analysis (PCA) and factor analysis (FA). In the second step, we test the
relationship between the dimensions and quality of papers (as measured by the
post-publication peer-review system of F1000Prime assessments) - using
regression analysis. The results of the PCA and FA show that altmetrics operate
along different dimensions, whereas Mendeley counts are related to citation
counts, and tweets form a separate dimension. The results of the regression
analysis indicate that citation-based metrics and readership counts are
significantly more related to quality, than tweets. This result on the one hand
questions the use of Twitter counts for research evaluation purposes and on the
other hand indicates potential use of Mendeley reader counts.
