Graficos malos en ecologia

Acabo de ver una pagina interesante del departamento de Estadistica de Vanderbilt University. Aparentemente el departamento tiene la politica de prohibir el uso de untipo de grafico que sigue siendo injustamente  popular en Ecologia, los “dynamite plots”. Una vez un arbitro me regaño por haber usado un grafico de barras de este tipo. Tenia mucha razón. Son malos.

Entonces, llevo varios años diciendo a los estudiantes que odio estos graficos. Normalmente un boxplot o dotplot es mejor. Al mismo tiempo  llevo años escuchando la respuesta por parte de otros tutores de que  boxplots son “meramente descriptivos”. Hay que publicar graficos de barras con “intervalos de confianza”, aun cuando los intervalos de confianza son engañosos y mal fundamentado porque los arbitros prefieran este tipo de grafico.

Yo por mi parte simplemente quiero ver los datos, no los supuestos.

Good Statistical Practice

General

Graphics

At a department meeting on 18Oct06, statisticians in the department voted in favor of the following policy:

  • In a small dataset (e.g., < 15 observations per category) it is mandatory to show the raw data in a graphic in a publication, and this cannot be done with dynamite plots (bar charts with error bars). Example

The vote was 22 in favor, 3 against. All 3 against would be in favor if “mandatory” were replaced with “usually”. Therefore the following is department policy:

  • Dynamite plots often hide important information. This is particularly true of small or skewed data sets. Researchers are highly discouraged from using them, and department members have the option to decline participation in papers in which the lead author requires the use of these plots.

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