Purpose: Citation-based assessments of countries' research capabilities often misrepresent their ability to achieve breakthrough advancements. These assessments commonly classify Japan as a developing country, which contradicts its prominent scientific standing. The purpose of this study is to investigate the underlying causes of such inaccurate assessments and to propose methods for conducting more reliable evaluations. Design/methodology/approach: The study evaluates the effectiveness of top-percentile citation metrics as indicators of breakthrough research. Using case studies of selected countries and research topics, the study examines how deviations from lognormal citation distributions impact the accuracy of these percentile indicators. A similar analysis is conducted using university data from the Leiden Ranking to investigate citation distribution deviations at the institutional level. Findings: The study finds that inflated lower tails in citation distributions lead to undervaluation of research capabilities in advanced technological countries, as captured by some percentile indicators. Conversely, research-intensive universities exhibit the opposite trend: a reduced lower tail relative to the upper tail, which causes percentile indicators to overestimate their actual research capacity. Research limitations: The descriptions are mathematical facts that are self-evident. Practical implications: Due to variations in citation patterns across countries and institutions, the Ptop 10%/P and Ptop 1%/P ratios are not universal predictors of breakthrough research. Evaluations should move away from these metrics. Relying on inappropriate citation-based measures could lead to poor decision-making in research policy, undermining the effectiveness of research strategies and their outcomes.