Sample size and optimal designs for reliability studies

Walter, Stephen D.; Eliasziw, Michael; Donner, Allan

doi:10.1002/(sici)1097-0258(19980115)17:1<101::aid-sim727>3.0.co;2-e

Cited by 1,801 publications

(1,168 citation statements)

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“…With a minimal acceptable intraclass correlation coefficient (ICC) of 0.80 and the hypothesis based on previous research (Vancampfort et al, 2011b;Vancampfort et al, 2012c) that present findings would be consistent with a minimum ICC of 0.90, a minimum sample size of 46 patients was required to attain a level of significance (α) of 0.05 and power of 0.8 (β = 0.2) (Donner and Eliasziw, 1987;Walter et al, 1998). Considering previous reliability studies in patients with schizophrenia (Vancampfort et al, 2011b;Vancampfort et al, 2012c), it was anticipated that approximately 15% of patients would be excluded a-priori, approximately 15% would decline participation for motivational reasons and approximately 15% would dropout from the testing for motivational or other reasons.…”

Section: Sample Size Analysissupporting

confidence: 70%

Reliability and clinical correlates of the Astrand–Rhyming sub-maximal exercise test in patients with schizophrenia or schizoaffective disorder

Vancampfort

Guelinckx

Hert

et al. 2014

Psychiatry Research

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Reliability and clinical correlates of the Astrand-Rhyming sub-maximal exercise test in patients with schizophrenia or schizoaffective disorder, Psychiatry Research, http://dx.doi.org/10.1016/j.psychres. 2014.08.049 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractCardiovascular fitness is reduced in people with schizophrenia and is related to an increased morbidity and mortality. There is mounting interest in the accurate measurement of cardiovascular fitness in schizophrenia, yet existing measures used in the general population have not been tested on validity and reliability in this high-risk group. Therefore, we examined the reproducibility and feasibility of the Astrand-Rhyming sub-maximal exercise test in patients with schizophrenia or schizoaffective disorder. Secondary aims were to assess minimal detectable changes, practice effects and the presence of clinical symptoms that are associated with cardio-respiratory fitness (expressed as estimated oxygen uptake). From 47 patients with schizophrenia or schizoaffective disorder two trials of the Astrand-Rhyming test, administered within three days, were analysed. The intraclass correlation coefficient for the estimated oxygen uptake between the two tests was 0.92 (95% confidence interval: 0.85 to 0.95). The minimal detectable change was 6.5mlO 2 /min/kg. No practice effect could be detected. A backward regression analysis demonstrated that illness duration, negative symptoms and level of physical activity explained 63.0% of the variance in estimated oxygen uptake. The current study demonstrates that the Astrand-Rhyming test can be recommended for evaluating the aerobic fitness in patients with schizophrenia or schizoaffective disorder.

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Section: Sample Size Analysissupporting

confidence: 70%

Reliability and clinical correlates of the Astrand–Rhyming sub-maximal exercise test in patients with schizophrenia or schizoaffective disorder

Vancampfort

Guelinckx

Hert

et al. 2014

Psychiatry Research

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“…The sample size calculation was based on detecting adequate reliability since this is an essential prerequisite to an instruments validity. To detect an agreement of 80%, with a power of 80% at the 5% significance level, a minimum of 40 fecal samples would have to be inspected by two nurses (Walter et al, 1998). Constraints upon nursing time prevented more than two nurses inspecting the same sample.…”

Section: Discussionmentioning

confidence: 99%

Assessment of fecal output in patients receiving enteral tube feeding: validation of a novel chart

2004

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Objective: To develop a practical, valid and reliable chart to assist in the accurate visual characterization of fecal output in patients receiving enteral tube feeding (ETF). Design: A chart incorporating verbal and pictorial descriptors of fecal output was developed. Validity and reliability were assessed by a questionnaire survey of health professionals and a clinical study of patients commencing ETF. Content validity was assessed from the results of the questionnaire, construct validity by contrasting groups analysis, concurrent validity by comparison of the chart with actual fecal weight and inter-rater reliability by independent characterization of the same fecal sample by two nurses. Setting: St George's Hospital, London, UK. Subjects: In all, 35 health professionals completed a questionnaire with respect to the chart. The chart was then used to monitor fecal output in 36 patients commencing ETF for a total of 171 patient-days, during which time nurses used the chart to characterize 269 fecal samples, of which 59 were subsequently weighed. Results: The results of the questionnaire suggested good content validity. The chart demonstrated statistically significant differences in fecal frequency, fecal consistency, fecal score and incidence of diarrhea for contrasting patient groups expected to have different fecal output (Po0.05). The inter-rater reliability was almost perfect for fecal consistency (95% agreement, k ¼ 0.91) and substantial for fecal weight (83%, k ¼ 0.75). In all, 83% of fecal samples were assigned to the correct weight category (k ¼ 0.75). Conclusion:The chart has good content, construct and concurrent validity and inter-rater reliability, and is suitable for both research and clinical use.

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“…The sample size (n = 17) was sufficient to characterize reliability where an ICC score of [0.6 was considered acceptable and an ICC of \0.2 was deemed unacceptable, with repeated measurements by three testers (power of 80% and alpha of 0.05) [50,54].…”

Section: Power Calculationmentioning

confidence: 99%

Preliminary study: reliability of the spinal wheel. A novel device to measure spinal postures applied to sitting and standing

et al. 2009

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Postural re-education is an integral part of physiotherapy management in patients with back pain. Although the link between posture and back pain is largely unknown, postural re-education is performed on the premise of optimizing spinal alignment to minimize stresses on the passive structures of the spine, to facilitate optimal muscular support and thus to prevent possible damage and further pain. A reliable and clinically meaningful measurement of spinal postures to monitor such interventions remains challenging. This study evaluated within-day (intra-tester, inter-tester) and between-day (test-retest) reliability of a novel spinal wheel device measuring thoracic and lumbar postures during sitting and standing. 17 healthy volunteers (age 39.5 ± 5.4, BMI 25 ± 9.2; 9 males) were measured three times, by three testers, on two separate occasions (1 week apart). The angular change between C7 and T12 and between T12 and S1 provided thoracic and lumbar curvatures, respectively. Intra-class correlation coefficient (ICC) with 95% confidence intervals and typical error were calculated. Excellent reliability was demonstrated with intra-tester ICCs between 0.947 and 0.980 and typical error between 1.7°and 3.7°and intertester ICCs between 0.949 and 0.986 and typical error between 2.0°and 4.7°. Test-retest reliability was high with ICCs 0.719-0.908 and typical error between 4.0°and 7.4°. In conclusion, the spinal wheel demonstrated excellent within-day and high between-day reliability. The device may be used in conjunction with 2D camcorder to provide clinically useful visual evaluation of postures for assessment, intervention monitoring, and feedback during postural re-education.

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Sample size and optimal designs for reliability studies

Cited by 1,801 publications

References 0 publications

Reliability and clinical correlates of the Astrand–Rhyming sub-maximal exercise test in patients with schizophrenia or schizoaffective disorder

Reliability and clinical correlates of the Astrand–Rhyming sub-maximal exercise test in patients with schizophrenia or schizoaffective disorder

Assessment of fecal output in patients receiving enteral tube feeding: validation of a novel chart

Preliminary study: reliability of the spinal wheel. A novel device to measure spinal postures applied to sitting and standing

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