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. 2021 Mar 31;45(1):239-257.
doi: 10.1007/s40614-021-00284-0. eCollection 2022 Mar.

Validity and Reliability Analysis of the PlotDigitizer Software Program for Data Extraction from Single-Case Graphs

Orhan Aydin  1 , Muhammed Yasin Yassikaya  2
Affiliations

Validity and Reliability Analysis of the PlotDigitizer Software Program for Data Extraction from Single-Case Graphs

Orhan Aydin et al. Perspect Behav Sci. .

Abstract

Access to raw data of graphs presented in original articles to calculate the effect size of single-case research is a challenge for researchers conducting studies such as meta-analysis. Researchers typically use data extraction software programs to extract raw data from the graphs in articles. In this study, we aimed to analyze the validity and reliability of the PlotDigitizer software program, which is widely used in literature and an alternative to other data extraction programs, on computers with different operating systems. We performed the digitization of 6.846 data points on three different computers using 15 hypothetical graphs with 20 data series and 186 graphs with 242 data series from 29 published articles to accomplish the goal. Besides, using the values we digitized, we recalculated the 23 effect sizes presented in the original articles for validity analysis. Based on our sampling, we calculated intercoder and intracoder Pearson correlation coefficients. The results showed that PlotDigitizer could be an alternative to other programs as it is free and can run on many current and outdated systems, and it is valid and reliable as it is nearly perfect. Based on the obtained results and considering the data extraction process, we presented various recommendations for the researchers that will use the PlotDigitizer program for the quantitative analysis of single-case graphs.

Keywords: Data extraction; PlotDigitizer; Reliability; Single-case design; Validity.

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Conflict of interest statement

Conflict of interestThere is no conflict of interest for the article.

Figures

Fig. 1
Fig. 1
Inter-coder and intra-coder scatterplot graphs according to the digitization of article graphs
Fig. 2
Fig. 2
Inter-coder and intra-coder scatterplot graphs according to the digitization of hypothetical data
Fig. 3
Fig. 3
Scatterplot graphs showing the correlation between the primary coder’s values and the actual vsalues
See this image and copyright information in PMC

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