--- title: "Bar charts enhance Bland-Altman plots. | Sutter Health" description: "This brief report shows how adding a simple bar chart to a Bland-Altman plot adds essential additional information." url: "https://www.sutterhealth.org/research/publications/bar-charts-enhance-bland-altman-plots-1055312551" --- 1. [Home](https://www.sutterhealth.org/) / 2. [Research](https://www.sutterhealth.org/research) / 3. [Research publications](https://www.sutterhealth.org/research/publications) / 4. Bar charts enhance Bland-Altman plots. # Bar charts enhance Bland-Altman plots when value ranges are limited. Smith MW, Ma J, & Stafford RS. _J Clin Epidemiol. 63(2):180-4. doi: 10.1016/j.jclinepi.2009.06.001. Epub 2009 Aug 27._ 2010-02-01 ## Abstract OBJECTIVE: A common form of validation study compares alternative methods for collecting data. The Bland-Altman plot pairs observations across methods and plots their mean values vs. their difference. This method provides only limited information, however, when the range of observed values is small relative to the number of observations. This brief report shows how adding a simple bar chart to a Bland-Altman plot adds essential additional information. STUDY DESIGN AND SETTING: The methodological approach is illustrated using data from a randomized controlled clinical trial of patients in a U.S. county health system. RESULTS: When the number of unique values is small, a Bland-Altman plot alone may provide inadequate information. Adding a bar chart yields new and essential information about agreement, bias, and heteroscedasticity. CONCLUSION: Studies validating one data-collection method against another can be performed successfully even when the number of unique values is small. [PubMed abstract](http://www.ncbi.nlm.nih.gov/pubmed/?term=Bar+Charts+Enhance+Bland-Altman+Plots+When+Value+Ranges+are) ## Research topics - [Biostatistics](https://www.sutterhealth.org/research-search-results?query=%22%5C%22Biostatistics%5C%22%22) ## Related publications [View all publications](https://www.sutterhealth.org/research-search-results?verticalKey=research_publication) - Publication ### [Algorithm for balancing both continuous and categorical covariates in randomized controlled trials](https://www.sutterhealth.org/research/publications/algorithm-balancing-covariates-rcts-1055312558) Xiao L, Yank V, Ma J. Comput Methods Programs Biomed. 108(3):1185-90. doi: 10.1016/j.cmpb.2012.06.001. 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Alexandria VA: American Statistical Association 2014; 1094-1100. 2014 Aug 06 [View all publications](https://www.sutterhealth.org/research-search-results?verticalKey=research_publication) ```json {"@context":"https://schema.org","@type":"MedicalOrganization","name":"Sutter Health","@id":"https://www.sutterhealth.org/#medicalorganization","url":"https://www.sutterhealth.org","logo":"https://www.sutterhealth.org/static/images/sutter-health-logo.svg","address":{"@type":"PostalAddress","streetAddress":"2200 River Plaza Drive","addressLocality":"Sacramento","addressRegion":"CA","postalCode":"95833","addressCountry":"US"},"areaServed":{"@type":"AdministrativeArea","name":"California"},"sameAs":["https://www.facebook.com/SutterHealth","https://www.instagram.com/sutterhealth/","https://x.com/SutterHealth","https://www.youtube.com/sutterhealth","https://www.linkedin.com/company/sutter-health","https://en.wikipedia.org/wiki/Sutter_Health"]} ``` ```json {"@context":"https://schema.org","@type":"BreadcrumbList","@id":"https://www.sutterhealth.org/research/publications/bar-charts-enhance-bland-altman-plots-1055312551#breadcrumblist","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://www.sutterhealth.org/"},{"@type":"ListItem","position":2,"name":"Research","item":"https://www.sutterhealth.org/research"},{"@type":"ListItem","position":3,"name":"Research publications","item":"https://www.sutterhealth.org/research/publications"},{"@type":"ListItem","position":4,"name":"Bar charts enhance Bland-Altman plots."}]} ``` ```json {"@context":"https://schema.org","@type":"MedicalScholarlyArticle","@id":"https://www.sutterhealth.org/research/publications/bar-charts-enhance-bland-altman-plots-1055312551#medicalscholarlyarticle","name":"Bar charts enhance Bland-Altman plots when value ranges are limited.","headline":"Bar charts enhance Bland-Altman plots.","abstract":"OBJECTIVE: A common form of validation study compares alternative methods for collecting data. 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