Sir, I read with interest the letter by Tovani-Palone.1 According to the recent Global Research Report by the Institute for Scientific Information, one-third of globally published articles have authors from different countries. Although international bilateral papers are the most common type of output at present, international trilateral and quadrilateral collaborations are on the rise. As citation counts tend to be greater when international collaboration is higher, it is essential to transform raw citation counts into 'normalised' counts against a relevant global benchmark for proper analysis of citation impact.2

The increasing level of international collaboration leads to complex credit attribution for authors. Thus, it becomes challenging to evaluate research productivity and citation impact. The assignment of fractional credit is potentially incorrect when the number of authors on individual publications increases significantly. Keeping these issues in mind, a method called the Collaborative Category Normalised Citation Impact (Collab-CNCI) was developed. It provides a transparent overall citation score by considering different levels of domestic and international authorship collaboration.3

This method provides a thorough understanding of a country's research portfolio. It takes into account the article and citation share for each collaboration type and normalises the cumulative citation counts for each paper against articles from the same publication year, subject category, document type, and the same collaboration type. The net CNCI for an author, institution, or country is the average CNCI of their papers.

Citations accrue differently depending on the discipline and document type. Citation counts and counting methods are crucial for performance evaluation at the individual, institutional, and national levels. The fractional and Collab-CNCI methods produce lower index values than the Standard CNCI, but Collab-CNCI provides insight into the role of collaboration in raising the indicator value. Compared to other CNCI indicators, it provides valuable information for decisions regarding research management and policy development. Through Collab-CNCI, research managers and funders can better contextualise relative performance and deconstruct research portfolios to make well-informed financing decisions.2,3