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An improved effect size for single-case research: nonoverlap of all pairs.

Parker, Richard I., Vannest, Kimberly·2009·Behavior Therapy

DOI 10.1016/j.beth.2008.10.006

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Abstract

Nonoverlap of All Pairs (NAP), an index of data overlap between phases in single-case research, is demonstrated and field tested with 200 published AB contrasts. NAP is a novel application of an established effect size known in various forms as Area Under the Curve (AUC), the Common Language Effect Size (CL), the Probability of Superiority (PS), the Dominance Statistic (DS), Mann-Whitney's U, and Sommers D, among others. NAP was compared with 3 other non-overlap-based indices: PND (percent of nonoverlapping data), PEM (percent of data points exceeding the median), and PAND (percent of all nonoverlapping data), as well as Pearson's R(2). Five questions were addressed about NAP: (a) typical NAP values, (b) its ability to discriminate among typical single-case research results, (c) its power and precision (confidence interval width), (d) its correlation with the established effect size index, R(2), and (e) its relationship with visual judgments. Results were positive, the new index equaling or outperforming the other overlap indices on most criteria.

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Statistical Power Analysis for the Behavioral Sciences
Muller, K. E., & Cohen, J. (1989) · Technometrics · doi:10.2307/1270020 · Cited by 99,603
Statistical power analysis for the behavioral sciences
Cohen, J. (1990) · Computers Environment and Urban Systems · doi:10.1016/0198-9715(90)90050-4 · Cited by 65,417
Statistical Power Analysis for the Behavioral Sciences (2nd ed.).
Lachenbruch, P. A., & Cohen, J. (1989) · Journal of the American Statistical Association · doi:10.2307/2290095 · Cited by 37,421
An analysis of variance test for normality (complete samples)
SHAPIRO, S. S., & WILK, M. B. (1965) · Biometrika · doi:10.1093/biomet/52.3-4.591 · Cited by 23,480
The meaning and use of the area under a receiver operating characteristic (ROC) curve.
Hanley, J. A., & McNeil, B. J. (1982) · Radiology · doi:10.1148/radiology.143.1.7063747 · Cited by 21,856
Practical Nonparametric Statistics
Groggel, D. J., & Conover, W. J. (2000) · Technometrics · doi:10.2307/1271101 · Cited by 11,076
The Use of Single-Subject Research to Identify Evidence-Based Practice in Special Education
Horner, R. H., Carr, E. G., Halle, J., McGee, G., Odom, S., & Wolery, M. (2005) · Exceptional Children · doi:10.1177/001440290507100203 · Cited by 3,368
Robust Tests for the Equality of Variances
Brown, M. B., & Forsythe, A. B. (1974) · Journal of the American Statistical Association · doi:10.1080/01621459.1974.10482955 · Cited by 3,216
Statistical methods in psychology journals: Guidelines and explanations.
Wilkinson, L., & Task Force on Statistical Inference (1999) · American Psychologist · doi:10.1037/0003-066x.54.8.594 · Cited by 2,791
Graphical Methods for Data Analysis.
Healy, M. J. R., Chambers, J. M., Cleveland, W. S., Kleiner, B., & Tukey, P. A. (1984) · Journal of the Royal Statistical Society Series A (General) · doi:10.2307/2981587 · Cited by 2,315

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“As a quasi-statistical procedure, the non-overlap of all pairs (NAP; Parker & Vannest, 2009) focuses on data overlap (i.e., what proportion of data points improves the measurements from the previous phase), with values between 0 and 0.66 indicating a small effect size, and those between 0.93 and…”
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“If the NAP effect size was calculated between 0.66 – 0.92, an intervention was categorized as showing a B medium ^ effect, and if the NAP effect size was calculated between 0 and 0.65, an intervention was categorized as showing a B weak ^ effect (Parker and Vannest 2009).”
MethodInfluential
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“In addition, we determined the overlap in data points using the nonoverlap of all pairs (NAP; Parker & Vannest, 2009), a nonparametric estimate of overlap derived by dividing the number of nonoverlapping pairs by the total number of pairs.”
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“follows: (a) small, 0% to 65%, (b) moderate, 66% to 92%, and (c) large, 93% to 100%.(39)”
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“TABLE 2 Single-case data with NAP for all 29 cases.”
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“…the analysis of the two-standard deviation bands (Perdices & Tate, 2009), while treatment effect and effect size were analysed through the study of data overlap by the computation of two statistical measures: Tau-U (Lee & Cherney, 2018) and non-overlap of all pairs (NAP; Parker & Vannest, 2009).”
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“Parker and Vannest (2009) reported 0 to .65 as a small effect, .66 to .92 as a medium effect, and .93 to 1 as a large effect.”
Background
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“Advantages of NAP include less room for human error, greater discrimination within or between single-case studies, stronger validation by both visual analysis and R 2, and narrower confidence intervals, which reflect greater precision (Parker & Vannest, 2009).”
Method
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“We calculated the Non-Overlap of All Pairs (NAP; Parker & Vannest, 2009) to evaluate improvement in child behavior across intervention phases.”
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“Parker and Vannest (2009) did provide a tentative interpretation scale for NAP, analogous to that used in PND, based on a process of expert judgements of 200 data sets.”
BackgroundMethodResultInfluential
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“The intervention effect size (NAP) was weak (ES ¼ .62; Parker & Vannest, 2009).”
Background
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“Regarding quantifications, the statistical analysis included the following techniques: PND (Scruggs et al., 1987), NAP (Parker & Vannest, 2009), Tau-U (Parker, Vannest, Davis, & Sauber, 2011; using the R code described in Brossart, Vannest, Davis, & Patience, 2014, downloaded from https://…”
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“Although there are no published guidelines for interpreting Tau-U, the existing guidelines for interpretation of NAP offer a conservative estimate of effect considering trend control available in Tau-U.”
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“Other methods to accompany the visual analysis in single-subject research are, for example, the celeration line, the C-statistic,(49) the percentage of nonoverlapping data(51) and the nonoverlap of all pairs method.(52) These were not applicable on account of too few data points.”
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“Degree of change in ideographic measures was quantified through the proportion of non-overlapping data (PND) points method between paired phases (Parker & Vannest, 2009).”
Method
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Method
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“Non-overlap of all pairs (NAP) was used to calculate phase differences and effect sizes for the daily measures of social anxiety (modified version of SPRS) and undesired time awake (SOL WASO; Manolov et al., 2016; Parker and Vannest, 2009; Parker et al., 2011).”
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“The effect sizes were medium (Parker & Vannest, 2009).”
Background
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“Tau-U scores are interpreted as 0.93 to 1.0 = large effect, 0.66 to 0.92 = medium effect, and 0 to 0.65 = small effect (Parker & Vannest, 2009).”
Influential
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“NAP is an estimate of the likelihood that a randomly selected intervention data point is an improvement over a randomly selected baseline data point (Parker & vannest, 2009).”
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“Thus, an additional technique, the nonoverlap of all pairs (NAP), was calculated for all single-case designs to include a comparable effect size calculation (Parker & Vannest, 2009).”
BackgroundMethod
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“Nonoverlap of All Pairs (NAP) was also calculated within each condition across all students: this calculation compares the number of times a child improved from pre- to posttest with the number of times the child did not improve (Parker & Vannest, 2009).”
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“Once the data were processed, we used the Nonoverlap of All Pairs (NAP) index [73] to measure the probability that a behavioral feature value drawn at random from any episode day would exceed that of a feature value drawn at random from any nonepisode day.”
Influential

Authors: Parker, R. I., & Vannest, K.
Affiliations: Texas A&M University (US)
Corresponding author: Parker, Richard I.
ORCID: Vannest, Kimberly
Venue: Behavior Therapy
Publisher: Elsevier BV
Published: 2009-12
Volume: 40
Issue: 4
Pages: 357-367
ISSN: 0005-7894 (ISSN-L)
DOI: 10.1016/j.beth.2008.10.006
OpenAlex: W2028628292
Cited by: 1,126
References: 65
Citations by year: 2026: 61 · 2025: 95 · 2024: 85 · 2023: 97 · 2022: 99 · 2021: 90 · 2020: 87 · 2019: 81 · 2018: 86 · 2017: 84 · 2016: 69 · 2015: 57 · 2014: 49 · 2013: 30 · 2012: 35
FWCI: 12.23
Type: journal article
Language: en
Open access: closed
Licence: www.elsevier.com/tdm/userlicense/1.0/ (tdm)
Locations: Behavior Therapy (publishedVersion)
PubMed (publishedVersion)
Topics: Social Sciences › Psychology › Developmental and Educational Psychology › Behavioral and Psychological Studies
Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
Social Sciences › Psychology › Experimental and Cognitive Psychology › Psychology Research and Bibliometrics
Keywords: effect size, single subject research, data overlap, R-squared, visual assessment, confidence interval width, statistical power
MeSH terms: Humans, Models, Psychological, Probability, Psychology, Research Design, Confidence Intervals, Area Under Curve

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An improved effect size for single-case research: nonoverlap of all pairs.

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