Operationalizing near‑death experiences: Stability of the NDE Rasch hierarchy over two decades.

Two scales measuring the phenomenology of near-death experiences—the 16-item NDE Scale and the 20-item NDE-C—were compared in 705 self-identified experiencers. The scales correlate nearly perfectly (r = 0.98), indicating they measure the same underlying construct. However, Rasch analysis revealed problems with the NDE-C's category structure and five novel items. The original NDE Scale's item hierarchy replicated across samples, showing long-term stability. Based on parsimony and psychometric evidence, the original NDE Scale with Rasch scoring and a validated cut-off of 7 (out of 32) is recommended for future research.

Study at a glance

Abstract

This study presents the first comprehensive psychometric comparison of Greyson's (1983) 16-item Near-Death Experience Scale (NDE Scale) and Martial et al.'s (2020) 20-item Near-Death Experience Content Scale (NDE-C) using Rasch modeling and differential item functioning (or response bias) analyses. A total of 705 self-identified "near-death experiencers" (64% women) completed both measures, which were randomly intermingled and rated for experiential relevance. Results confirmed that the two scales measure the same underlying construct of NDE phenomenology, as evidenced by a near-perfect disattenuated Pearson correlation (r = 0.98, p < 0.001). However, Rasch analysis revealed limitations in the category structures of both scales-particularly the NDE-C-and identified psychometric and conceptual weaknesses in its five novel items. Critically, the core Rasch item hierarchy derived from the original NDE Scale was replicated both in this sample and a previously simulated dataset based on the NDE-C's development research, confirming its long-term structural stability. Based on the present evidence and the principle of parsimony, we recommend the original NDE Scale supported by Rasch scoring and a validated cut-off of 7 (out of 32), as it is conceptually coherent and psychometrically robust, while maintaining historical comparison with previous research. These findings reinforce the value of Rasch modeling for cumulative theory-building and underscore the Rasch NDE hierarchy's foundational role in operationalizing legitimate near-death experiences.