Research metrics

These pages set out some guidance on using and understanding some commonly encountered types of metrics:

• Citation counts
• Impact factors
• The h-index
• Normalised metrics (CNCI, percentiles)

Citation metrics can be informative, and tell us a lot about the reception of a piece of research. However, simple citation counts can potentially be distorted by factors such as age, and for any kind of detailed bibliometric analysis or comparison, we would recommend using the standard normalised metrics (CNCI and percentile ranks).

We recommend avoiding the journal impact factor or the h-index; these are two commonly seen metrics that often give misleading results.

UCL is a signatory to the San Francisco Declaration on Research Assessment (DORA), which initially focused on the misuse of the impact factor, but who have also provided their own guidance on using specific indicators including the h-index, citation counts, and altmetrics.