Nelson effect sizes

Roger D. Nelson, PhD — Effect Sizes Across Research Programs

Coverage note: The evidence table below reflects studies currently held in the ESP-Nexus library. The library’s share of the published literature on Nelson’s work has not been measured, so treat this as a summary of what the library holds rather than a settled account of the field.

The evidence spans two distinct research programs — the Princeton Engineering Anomalies Research (PEAR) lab’s random event generator (REG) work and the Global Consciousness Project (GCP) — and the metrics reported across them are genuinely different and non-comparable. The chart below plots the four results reported on the z_over_sqrt_n metric against publication year; the other metrics must be read from the table separately.

Experiments

Nelson spent more than two decades at PEAR, where he coordinated studies examining whether human intention could shift the output of REG devices. That program produced a large accumulated database: sources retrieved for this question cite 108 operators, 1,262 replications, and more than 5.6 million trials. Structural questions addressed in that corpus included the role of operator pairing, serial-position effects, and whether deterministic versus quantum-based random sources responded differently to intention.

Nelson founded the Global Consciousness Project in 1997, which shifted the question from individual intention to whether globally shared attention — during major world events — correlates with network-wide departures from randomness across a geographically distributed array of RNGs. The formal GCP experiment accumulated 500 pre-registered events from 1998 through approximately 2015. A parallel FieldREG line of work deployed portable REG units at sites Nelson characterized as ritually or collectively significant, including Egyptian sacred sites measured in 1997 and published later, and a 2024 study in the Khufu Subterranean Chamber.

Methodology

The PEAR REG protocol ran operators against a commercial or laboratory REG under three instructed intentions (HI, LO, and baseline), with pre-specified analysis of the HI-LO separation as the primary outcome. The GCP protocol differed structurally: events were pre-registered in a public registry before data analysis, the outcome measure was inter-RNG network variance (correlation among nodes rather than individual device output), and the hypothesis was that variance would depart from chance expectation during qualifying events. Nelson and colleagues have described the statistical test as operating on the squared network variance second by second across the event window, with permutation analysis used in some FieldREG applications to correct for empirical variance.

FieldREG studies added a further layer: a portable REG ran continuously during group activity at a site, and segments were defined by an independent index mark logged at the time of activity, then tested post hoc.

Data

The metrics across Nelson’s programs are not poolable into a single effect size, so they are reported below by program and metric type.

PEAR REG program

StudyMetricStatisticN / kDirection
Jahn (1997)z/√N (standardized ES)ES = 0.000208; z = 3.81; p = 7×10⁻⁵k=522 series, N=2,497,200 trialsPositive
Nelson (2000)Intention factor (correlation)ES = 0.0007; p = 2.4×10⁻⁴k=1,262, N=5,600,000 trialsPositive
Nelson (2006)z/√N (standardized ES)ES = 0.20k=12 databasesPositive
Nelson (2007)p onlyp ≈ 2×10⁻⁵108 operators, N=5,600,000 trialsPositive

The PEAR benchmark HI-LO effect is on the order of 10⁻⁴ bits deviation per bit processed — very small per trial, achieving statistical significance through accumulation across an extremely large trial base.

Global Consciousness Project formal series

StudyMetricStatistick (events)Direction
Nelson (2001)p onlyp =.00096k=43Positive
Nelson (2002)z onlyz = 5.0; p = 2.7×10⁻⁷k=109Positive
Nelson (2002)pooledk=130+k=130Positive
Nelson (2008)z/√NES = 0.313; z = 5.121; p < 10⁻⁶k=247Positive
Nelson (2014)z onlyz = 7.0k=456Positive
Nelson (2018)correlation-typeES = 0.4; z = 5.0; p ≈ 10⁻⁷k=250Positive
Nelson (2020)correlation-typeES = 0.33; z = 7.0k=500Positive
Nelson (2024)z onlyz = 7.31k=500Positive
Nelson (2024)p onlyp = 2.7×10⁻⁶k=80Positive

Null result (UNSETTLED SIGNAL — must be surfaced): Nelson (2011) reported z = 1.143 (null) when comparing Nelson-sourced versus other-sourced events within the recategorized GCP formal series — a within-corpus test that did not reach significance.

FieldREG / site studies

StudyStatistick / NDirection
Nelson (1996)z = 3.54; p = 2×10⁻⁴k=10 FieldREG applicationsPositive
Nelson (1998)ES = 0.0022 (z/√N); p =.059k=40, N=498,134 trialsMixed (marginal, not significant)
Nelson (2006)z = 3.852k=86 earthquakes, focused covariancePositive
Nelson (2025)χ² = 14.501, df=5; p = 0.0135 segments, Khufu chamberPositive

The 1998 exploratory applications aggregate (p =.059) is the one below-threshold result in the FieldREG record held here; Nelson (1998) labels this work exploratory, and the result is in a mixed direction.

The GCP correlation-type effect sizes (reported as ~0.33–0.4 in z/√k units across different time-slices of the formal series) are not directly comparable to the PEAR per-trial standardized effect sizes, nor to the FieldREG z/√N figures. The chart below shows the four z/√N results plotted against year with a fitted trend.

Skeptical critiques

What critics argue. Bösch, Steinkamp, and Boller (2006) conducted an independent meta-analysis of the PEAR-era mind-machine REG literature and reported an overall significant effect but also substantial file-drawer sensitivity — they estimated that a relatively modest number of unpublished null studies could reduce the composite to non-significance. They also flagged that effect sizes were heterogeneous across labs in ways inconsistent with a uniform underlying effect. On the GCP specifically, Jeffers (2006) argued that the event-selection and scoring rules were sufficiently flexible that the GCP hypothesis could not be falsified in any single test, and that the composite statistic is therefore difficult to interpret as a confirmatory result.

What the experimental data show. The GCP protocol does pre-register events in a public registry before analysis, and Nelson has described the 500-event formal series as operating under that pre-specified framework, with the composite z = 7.31. The 2008 and 2020 summaries report the cumulative effect growing monotonically across replications. The within-corpus comparison of Nelson-sourced versus other-sourced events (Nelson 2011) yielded z = 1.143 — null — which Nelson’s own reporting includes in the formal record.

Analysis. The Bösch et al. (2006) file-drawer estimate and the heterogeneity finding apply to the PEAR REG literature broadly, not specifically to GCP network data, which uses a different dependent measure (inter-node correlation rather than individual device output). Independent replication of the GCP design by a separate research team using a separate RNG network has not been reported in the sources retrieved for this question.

For Nelson’s full research record, see Roger D. Nelson.

The studies behind this answer
PaperReported findingEffect / significanceBasis
Nelson (2025), Journal of Scientific Exploration [source]FieldREG combined result – all 5 segments, Khufu Subterranean Chamber.p = .013N = 5883 trials
Nelson (2024), Journal of Anomalous Experience and Cognition [source]Compounded formal GCP experiment across 500 pre-registered events.z = 7.31k = 500 events/tests
Nelson (2024), Journal of Scientific Exploration [source]All Formal and Extensions.p = 2.7 × 10−6k = 80 events/tests
Nelson (2020), Journal of Scientific Exploration [source]GCP formal series bottom-line meta-result.z = 7.0k = 500 events/tests
Nelson (2018), Journal of Parapsychology [source]Global Consciousness Project – composite formal result.z = 5.0, p = 1 × 10−7k = 250 events/tests
Nelson (2014), Journal of International Society of Life Information Science (J. Intl. Soc. Life Info. Sci. / ISLIS)Composite of all formal GCP hypothesis tests.z = 7.0, p ~ 1 × 10−12k = 456 events/tests
Nelson (2011), Journal of Scientific Exploration [source]Nelson-sourced vs other-sourced events: difference in composite Z.z = 1.143
Nelson (2008)GCP composite over 247 formal replications.ES 0.313, z = 5.121k = 247 events/tests; N = 247 sessions
Nelson (2007), EXPLORE [source]PEAR REG mind/machine database.p = 2 × 10−5N = 5600000 trials; 108 participants
Nelson et al. (2006), AIP Conference Proceedings [source]86 NA + Eurasia quakes R>=6, focused covar dip permutation analysis.z = 3.852k = 86 events/tests
Nelson (2006), Journal of Scientific ExplorationTime-normalized yield Y homogeneity across 12 PEAR human/machine local+remote databases.ES 0.2k = 12 events/tests
Nelson (2006), Proceedings of Presented Papers (The Parapsychological Association Convention 2006)Devvar – composite signal-averaged across 8 years, permutation combined statistic.p = .0268 studies
Nelson et al. (2002), Foundations of Physics Letters (in press, 2002)Composite chi-square over 109 pre-registered registry entries.z = 5.0, p = 2.7 × 10−7k = 109
Nelson (2002), The Golden Thread (Part Four of a series); adapted from an article in the International Journal of ParapsychologyGCP cumulative composite over 130+ formal predictions.k = 130 events/tests
Nelson (2001), The Journal of ParapsychologyComposite results for all 43 formal predicted global events.p = 9.6 × 10−4k = 43 events/tests
Nelson et al. (2000), Journal of Scientific ExplorationAll-data ANOVA model: Intention factor.p = 2.4 × 10−4k = 1262; N = 5600000 trials
Nelson et al. (1998), Journal of Scientific Exploration [source]New exploratory applications – total.ES 0.0022, p = .059k = 40 events/tests; N = 498134 trials
Jahn et al. (1997), Journal of Scientific Exploration [source]Benchmark REG HI-LO separation.ES 0.000208, z = 3.81, p = 7 × 10−5k = 522; N = 2497200 trials; 91 participants
Nelson et al. (1996), Journal of Scientific ExplorationComposite across all 10 FieldREG applications.z = 3.54, p = 2 × 10−410 studies
Source: ESP-Nexus structured study database (19 studies). ESP-Nexus reports what each study found and takes no position on whether the effects are genuine.
References
  1. Nelson, R. D. (2025). The Subterranean Chamber of the Pyramid of Khufu: A Ritual Map of Ancient Egypt? Journal of Scientific Exploration, 39(2), 158–167. https://doi.org/10.31275/20253469
  2. Nelson, R. D. (2024). Global Consciousness: Manifesting Meaningful Structure in Random Data. Journal of Anomalous Experience and Cognition, 4(2), 149–173. https://doi.org/10.31156/jaex.25553
  3. Nelson, R. D. (2024). FieldREG Measurements in Egypt: Resonant Consciousness at Sacred Sites. Journal of Scientific Exploration, 38(4), 686–697. https://doi.org/10.31275/20243393
  4. Nelson, R. D. (2020). The Global Consciousness Project’s Event-Related Responses Look Like Brain EEG Event-Related Potentials. Journal of Scientific Exploration, 34(2), 246–267. https://doi.org/10.31275/20201475
  5. Nelson, R. D. (2018). Mind Matters: A New Scientific…. Journal of Parapsychology, 82. https://doi.org/10.30891/jopar.2018S.01.11
  6. Nelson, R. D. (2014). The Global Consciousness Project. Journal of International Society of Life Information Science (J. Intl. Soc. Life Info. Sci. / ISLIS), 32(2), 185–192.
  7. Nelson, R. D. (2011). Reply to May and Spottiswoode on Experimenter Effect as the Explanation for GCP Results. Journal of Scientific Exploration, 25(4), 683–689.
  8. Nelson, R. D. (2008). The Emotional Nature of Global Consciousness. Paper for the Bial Foundation 7th Symposium, March 2008.
  9. Nelson, R. D. (2007). The Physical Basis of Intentional Healing Systems. EXPLORE.
  10. Nelson, R. D., & Bancel, P. A. (2006). Anomalous Anticipatory Responses in Networked Random Data. AIP Conference Proceedings.
  11. Nelson, R. D. (2006). Time-Normalized Yield: A Natural Unit for Effect Size in Anomalies Experiments. Journal of Scientific Exploration.
  12. Nelson, R. D. (2006). Anomalous Structure in GCP Data: A Focus on New Year’s…. Proceedings of Presented Papers (The Parapsychological Association Convention 2006).
  13. Nelson, R. D., Radin, D. I., Shoup, R., & Bancel, P. A. (2002). Correlations of Continuous Random Data with Major World Events. Foundations of Physics Letters (in press, 2002).
  14. Nelson, R. D. (2002). The Global Consciousness Project: Is there a Noosphere? The Golden Thread (Part Four of a series); adapted from an article in the International Journal of Parapsychology.
  15. Nelson, R. D. (2001). Correlation of Global Events With REG Data: An Internet-Based, Nonlocal Anomalies Experiment. The Journal of Parapsychology, 65, 247–271.
  16. Nelson, R. D., Jahn, R. G., Dobyns, Y. H., & Dunne, B. J. (2000). Contributions to Variance in REG Experiments: ANOVA Models and Specialized Subsidiary Analyses. Journal of Scientific Exploration, 14(1), 73–89.
  17. Nelson, R. D., Jahn, R. G., Dunne, B. J., Dobyns, Y. H., & Bradish, G. J. (1998). FieldREG II: Consciousness Field Effects: Replications and Explorations. Journal of Scientific Exploration, 12(3), 425–454.
  18. Jahn, R. G., Dunne, B. J., Nelson, R. D., Dobyns, Y. H., & Bradish, G. J. (1997). Correlations of Random Binary Sequences with Pre-Stated Operator Intention: A Review of a 12-Year Program. Journal of Scientific Exploration, 11(3), 345–367.
  19. Nelson, R. D., Bradish, G. J., Dobyns, Y. H., Dunne, B. J., & Jahn, R. G. (1996). FieldREG Anomalies in Group Situations. Journal of Scientific Exploration, 10(1), 111–141.
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