Tim Rakow1, Rebecca J Wright1, Catherine Bull2, David J Spiegelhalter3. 1. University of Essex, Colchester, United Kingdom (TR, RJW) 2. Hospital for Sick Children, Great Ormond Street, London, United Kingdom (KB) 3. University of Cambridge, Cambridge, United Kingdom (DJS)
Abstract
UNLABELLED: OBJECTIVE AND SAMPLE: This investigation assessed the comprehension of survival curves in a community sample of 88 young and middle-aged adults when several aspects of good practice for graphical communication were implemented, and it compared comprehension for alternative presentation formats. DESIGN, METHOD, and MEASUREMENTS: After reading worked examples of using survival curves that provided explanation and answers, participants answered questions on survival data for pairs of treatments. Study 1 compared presenting survival curves for both treatments on the same figure against presentation via 2 separate figures. Study 2 compared presenting data for 3 possible outcome states via a single "multistate" figure for each treatment against presenting each outcome on a separate figure (with both treatments on the same figure). Both studies compared alternative forms of questioning (e.g., "number alive" versus "number dead"). Numeracy levels (self-rated and objective measures) were also assessed. RESULTS: Comprehension was generally good--exceeding 90% correct answers on half the questions--and was similar across alternative graphical formats. Lower accuracy was observed for questions requiring a calculation but was significantly lower only when the requirement for calculation was not explicit (13%-28% decrements in performance). In study 1, this effect was most acute for those with lower levels of numeracy. Subjective (self-rated) numeracy and objective (measured) numeracy were both moderate positive predictors of overall task accuracy (r ≈ 0.3). CONCLUSIONS: A high degree of accuracy in extracting information from survival curves is possible, as long as any calculations that are required are made explicit (e.g., finding differences between 2 survival rates). Therefore, practitioners need not avoid using survival curves in discussions with patients, although clear and explicit explanations are important.
UNLABELLED: OBJECTIVE AND SAMPLE: This investigation assessed the comprehension of survival curves in a community sample of 88 young and middle-aged adults when several aspects of good practice for graphical communication were implemented, and it compared comprehension for alternative presentation formats. DESIGN, METHOD, and MEASUREMENTS: After reading worked examples of using survival curves that provided explanation and answers, participants answered questions on survival data for pairs of treatments. Study 1 compared presenting survival curves for both treatments on the same figure against presentation via 2 separate figures. Study 2 compared presenting data for 3 possible outcome states via a single "multistate" figure for each treatment against presenting each outcome on a separate figure (with both treatments on the same figure). Both studies compared alternative forms of questioning (e.g., "number alive" versus "number dead"). Numeracy levels (self-rated and objective measures) were also assessed. RESULTS: Comprehension was generally good--exceeding 90% correct answers on half the questions--and was similar across alternative graphical formats. Lower accuracy was observed for questions requiring a calculation but was significantly lower only when the requirement for calculation was not explicit (13%-28% decrements in performance). In study 1, this effect was most acute for those with lower levels of numeracy. Subjective (self-rated) numeracy and objective (measured) numeracy were both moderate positive predictors of overall task accuracy (r ≈ 0.3). CONCLUSIONS: A high degree of accuracy in extracting information from survival curves is possible, as long as any calculations that are required are made explicit (e.g., finding differences between 2 survival rates). Therefore, practitioners need not avoid using survival curves in discussions with patients, although clear and explicit explanations are important.
Authors: Eric S Kiechle; Stacy Cooper Bailey; Laurie A Hedlund; Anthony J Viera; Stacey L Sheridan Journal: J Gen Intern Med Date: 2015-04-28 Impact factor: 5.128
Authors: Ruth H Keogh; Diana Bilton; Rebecca Cosgriff; Dominic Kavanagh; Oliver Rayner; Philip M Sedgwick Journal: PLoS One Date: 2019-04-12 Impact factor: 3.240