The goal of forensicdatatoolkit is to combine several tools created for investigating summary data and detect anomalies. This is not a tool for finding fraud. Fraud is a legal term. These tools merely tell you if the underlying data is probable or not. It can never tell us why the statistics are wrong. Someone could lie or someone could mistype a number. Only open data can tell us which it is.
You can install the released version of forensicdatatoolkit from CRAN with:
install.packages("forensicdatatoolkit")library(forensicdatatoolkit)What is in the package.
- Granularity-Related Inconsistency of Means (GRIM)
- [] Granularity-Related Inconsistency of Means Mapped to Error Repeats (GRIMMER)
- Sample Parameter Reconstruction via Iterative Techniques (SPRITE)
- (DEBIT): A simple consistency test for binary data
We can use these tools to investigate summary statistics. For example if we collect statistics from a set of papers we can investigate them.
Let’s imagin we have 2 published papers about food. The author let several people taste chocolate bars and judge those bars. We use:
- a 1-5 scale for food acceptance
- a 1-9 scale for how dark the chocolate was and,
- a 1-7 scale for if you like the chocolate
The study only reports the summary statistics (means and standard deviations) for every scale.
example_data <- data.frame(
study = c(1, 1, 1, 2, 2, 2),
description = rep(c("food acceptance", "darkness", "likeability"), 2),
n = c(20, 19, 19, 40, 41, 40),
means = c(3.50, 5.60, 2.13, 2.54, 8.00, 3.05),
sds = c(1.34, 1.34, 2.56, 0.45, 2, 1),
scale_min = rep(c(1, 1, 1), 2),
scale_max = rep(c(5, 9, 7))
)
example_data
#> study description n means sds scale_min scale_max
#> 1 1 food acceptance 20 3.50 1.34 1 5
#> 2 1 darkness 19 5.60 1.34 1 9
#> 3 1 likeability 19 2.13 2.56 1 7
#> 4 2 food acceptance 40 2.54 0.45 1 5
#> 5 2 darkness 41 8.00 2.00 1 9
#> 6 2 likeability 40 3.05 1.00 1 7It is possible that the researcher dropped some chocolate on his work when the values were being calculated. Fortunately we can do a granularity check on the means to see if those means are possible given the scale used, and the sample size. This check is known as the GRIM test (Granularity-Related Inconsistency of Means). [LINK TO PREPRINT HERE].
Let’s use an example: 20 people each picked an integer between 1 and 5 (because you cannot choose someting else). What happens to the mean score if one person went from 1: disgusting to 2:awful? the mean score would go up by 1/20th. The minimal stepsize is 1/20th or 0.05. That means that every mean must be divisable by that stepsize. 3.5 is therefore fine but 3.53 is not.
example_data$mean_possible <- check_mean(example_data$means, example_data$n)
example_data[, c("study", "description", "mean_possible")]
#> study description mean_possible
#> 1 1 food acceptance TRUE
#> 2 1 darkness FALSE
#> 3 1 likeability FALSE
#> 4 2 food acceptance FALSE
#> 5 2 darkness TRUE
#> 6 2 likeability TRUEThis also works with tidyverse verbs **click here to unhide code**
library(dplyr)
example_data %>%
mutate(
mean_possible = check_mean(mean = means, n = n)
) %>%
select(study, description, mean_possible)Please note that the ‘forensicdatatoolkit’ project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.
At the moment of creation (when I knitted this document ) this was the state of my machine: **click here to expand**
sessioninfo::session_info()
#> ─ Session info ───────────────────────────────────────────────────────────────
#> setting value
#> version R version 3.6.3 (2020-02-29)
#> os macOS Mojave 10.14.6
#> system x86_64, darwin15.6.0
#> ui X11
#> language (EN)
#> collate en_US.UTF-8
#> ctype en_US.UTF-8
#> tz Europe/Amsterdam
#> date 2020-05-04
#>
#> ─ Packages ───────────────────────────────────────────────────────────────────
#> package * version date lib source
#> assertthat 0.2.1 2019-03-21 [1] CRAN (R 3.6.0)
#> cli 2.0.2 2020-02-28 [1] CRAN (R 3.6.0)
#> colorspace 1.4-1 2019-03-18 [1] CRAN (R 3.6.0)
#> crayon 1.3.4 2017-09-16 [1] CRAN (R 3.6.0)
#> digest 0.6.25 2020-02-23 [1] CRAN (R 3.6.0)
#> dplyr 0.8.5 2020-03-07 [1] CRAN (R 3.6.0)
#> ellipsis 0.3.0 2019-09-20 [1] CRAN (R 3.6.0)
#> evaluate 0.14 2019-05-28 [1] CRAN (R 3.6.0)
#> fansi 0.4.1 2020-01-08 [1] CRAN (R 3.6.0)
#> forensicdatatoolkit * 0.0.0.9000 2020-05-04 [1] local
#> ggplot2 3.3.0 2020-03-05 [1] CRAN (R 3.6.0)
#> glue 1.4.0 2020-04-03 [1] CRAN (R 3.6.2)
#> gtable 0.3.0 2019-03-25 [1] CRAN (R 3.6.0)
#> htmltools 0.4.0 2019-10-04 [1] CRAN (R 3.6.0)
#> knitr 1.28 2020-02-06 [1] CRAN (R 3.6.0)
#> lifecycle 0.2.0 2020-03-06 [1] CRAN (R 3.6.0)
#> magrittr 1.5 2014-11-22 [1] CRAN (R 3.6.0)
#> munsell 0.5.0 2018-06-12 [1] CRAN (R 3.6.0)
#> pillar 1.4.3 2019-12-20 [1] CRAN (R 3.6.0)
#> pkgconfig 2.0.3 2019-09-22 [1] CRAN (R 3.6.0)
#> purrr 0.3.3 2019-10-18 [1] CRAN (R 3.6.0)
#> R6 2.4.1 2019-11-12 [1] CRAN (R 3.6.0)
#> Rcpp 1.0.4.6 2020-04-09 [1] CRAN (R 3.6.3)
#> rlang 0.4.5 2020-03-01 [1] CRAN (R 3.6.0)
#> rmarkdown 2.1 2020-01-20 [1] CRAN (R 3.6.0)
#> scales 1.1.0 2019-11-18 [1] CRAN (R 3.6.0)
#> sessioninfo 1.1.1 2018-11-05 [1] CRAN (R 3.6.0)
#> stringi 1.4.6 2020-02-17 [1] CRAN (R 3.6.0)
#> stringr 1.4.0 2019-02-10 [1] CRAN (R 3.6.0)
#> tibble 3.0.0 2020-03-30 [1] CRAN (R 3.6.2)
#> tidyselect 1.0.0 2020-01-27 [1] CRAN (R 3.6.0)
#> vctrs 0.2.4 2020-03-10 [1] CRAN (R 3.6.0)
#> withr 2.1.2 2018-03-15 [1] CRAN (R 3.6.0)
#> xfun 0.13 2020-04-13 [1] CRAN (R 3.6.2)
#> yaml 2.2.1 2020-02-01 [1] CRAN (R 3.6.0)
#>
#> [1] /Library/Frameworks/R.framework/Versions/3.6/Resources/library
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