question: OBJECTIVES: This study aimed to identify typical patterns and determinants of early-career nurse researchers (ECNRs: age ≤45 years) who reported that their research activities were negatively impacted during the COVID-19 pandemic, using a data mining methodology. To gain a deeper understanding of the characteristics of these ECNRs, we compared them with the characteristics of senior nurse researchers (SNRs: age ≥46 years). DESIGN: A cross-sectional study. PARTICIPANTS: 1532 nurse researchers. DATA COLLECTION AND ANALYSIS: We conducted an anonymous online questionnaire survey that assessed individual and professional attributes of nurse researchers and their experiences from April to June 2020. We analysed the association between the impact on research activities and the individual and professional attributes using cross-tabulation, and employed the chi-square automatic interaction detection technique to perform population segmentation. RESULTS: We found that difficulties in research management, an increased burden of student education and organisational management, and organisational management position were relatively important factors for determining the negative impact of COVID-19 on the research activities of ECNRs (p<0.05). For both ECNRs and SNRs, the most relevant determinant of disrupted research activities was ‘difficulties in research management’ (χ(2)=34.7 and 126.5, respectively, p<0.001 for both). However, only ECNRs yielded ‘position in organisational management’ and was extracted only for ECNRs (χ(2)=7.0, p=0.008). CONCLUSIONS: Difficulties in research management and an increased burden of student education and organisational management had an unfavourable impact on the research activities of ECNRs. To ensure quality of nursing care and nursing science development during and after the COVID-19 era, it is important to support ECNRs in their nursing research activities and career development. Our findings could contribute to the prioritisation of interventions and policymaking for ECNRs who are particularly at risk of being negatively affected by the pandemic.