  We investigate the changes in the self-citation behavior of Italian
professors following the introduction of a citation-based incentive scheme, for
national accreditation to academic appointments. Previous contributions on
self-citation behavior have either focused on small samples or relied on simple
models, not controlling for all confounding factors. The present work adopts a
complex statistics model implemented on bibliometric individual data for over
15,000 Italian professors. Controlling for a number of covariates (number of
citable papers published by the author; presence of international authors;
number of co-authors; degree of the professor's specialization), the average
increase in self-citation rates following introduction of the ASN is of 9.5%.
The increase is common to all disciplines and academic ranks, albeit with
diverse magnitude. Moreover, the increase is sensitive to the relative
incentive, depending on the status of the scholar with respect to the
scientific accreditation. A further analysis shows that there is much
heterogeneity in the individual patterns of self-citing behavior, albeit with
very few outliers.
