This article aims to review the literature on customer relationship management (CRM) research. This review article analyses the trends in CRM research, popular research topics and tools used in studies. This study presents how CRM research developed over 21 years in terms of critical areas, type of studies, sources of papers, the origin of articles (country-wise distribution), type of data used, under-researched areas and popular researched areas. The study provides a broad classification and summarizes the last 21 years of CRM research in an organized way. For this review article, research papers were taken from January 2000 to June 2020, that is, 21 years. A total of 104 papers were selected from different journals and conferences. Findings show that most of the articles were published in the year 2009. A total of 95% of articles were published in journals, and 5% were conference papers—most of the CRM research done in the USA and the United Kingdom. Empirical papers were maximum in number, whereas case studies were least. Primary studies were more than secondary studies. In review papers, the maximum times CRM and electronic customer relationship management (E-CRM) were taken as a basis for reviewing. The further article has classifications within primary studies and review papers. It also presents the most frequently used keywords and variables in literature. The study will be useful for researchers, practitioners and academicians for further CRM research. This study also provides the classification within primary studies based on data collection tools used, sampling technique used, sampling country, industry, statistical tests and methods and software used, also it gives a brief view of keywords and variables used in a total of 104 papers. This article provides the first such review on keywords and variables, thus presenting the classification on a different basis, which none of the published research has presented.
Stored only when both papers are in the corpus — 85 citations exist upstream.