2.4.4 The number of citations for my paper is too low

Publish or Perish uses Google Scholar data to calculate its citation metrics. Google Scholar's processing is automatic (unlike ISI's that involves manual handling and checking, with the associated price tag) and hence occasional errors or omissions do occur.

This may be due to:

For more information limitations of Google Scholar, see Chapter 13 which discusses the advantages and disadvantages of the different data sources for citation analyses.