A new set of heuristic indicators is presented for the evaluation of the accessibility of statistical charts for people with impaired vision and color vision deficiency (CVD), as well as a methodology for their application. To validate the proposal, a heuristic evaluation of the accessibility of 35 charts published in 5 Spanish and 2 international newspapers is carried out. The results show that the proposed indicators enable the detection of a greater number of unique problems, present a better distribution of problems among heuristics, and enable the detection of more severe and specific problems compared with the Web content accessibility guidelines (WCAG). Regarding the problems detected, the lack of text alternatives to charts in bitmap format stands out, a problem that also occurs in the case of charts in SVG format, for which standards such as WAI-ARIA are not used for labeling the marks. The latter also underlines the poor use of indicators to highlight the elements that receive focus, or their inaccessibility through a keyboard interface. Other common problems with both types of charts are the non-text contrast ratio, which in many cases is below the minimum required, too small a font size, or the non-systematization of the use of color palettes appropriate for people with CVD. The comparison between national and international media reveals that, although higher scores are obtained by international media, they share a significant number of the problems identified for Spanish media. The list of principles obtained, beyond proving helpful for evaluative purposes, is also useful as a guide for creating accessible charts that could be easily incorporated into the style guides of the analyzed media. Resumen Se presenta un nuevo conjunto de indicadores heurísticos para la evaluación de la accesibilidad de los gráficos estadísticos para personas con baja visión y visión cromática deficiente (VCD), así como un método para su aplicación. Con el objetivo de validar la propuesta, se ha realizado una evaluación heurística de la accesibilidad de 35 gráficos publicados en 5 diarios españoles y 2 internacionales. Los resultados muestran que los indicadores propuestos consiguen detectar una mayor cantidad de problemas únicos, presentan una mejor distribución de los problemas entre heurísticos y consiguen detectar problemas más severos y específicos que las Web content accessibility guidelines (WCAG). En relación con los problemas detectados, destaca la prácticamente nula presencia de alternativas textuales en los gráficos publicados como imágenes en formato de mapa de bits, un problema que también se da en el caso de los gráficos publicados en formato SVG, donde destaca el nulo etiquetado de las marcas con estándares como WAI-ARIA. En estos últimos también se observa el pobre uso de indicadores para remarcar los elementos que reciben el foco, o su inaccesibilidad mediante una interfaz de teclado. Otros problemas comunes en ambos tipos de gráficos son la ratio de contraste entre elementos no textuales, por debajo en muchos casos del mínimo requerido, un tamaño de fuente demasiado pequeño o la no sistematización del uso de paletas de colores seguras para personas con VCD. Por lo que respecta a la comparación entre medios nacionales e internacionales, si bien las puntuaciones obtenidas por los internacionales son superiores, éstos comparten un importante número de problemas con los españoles. La lista de indicadores obtenida, más allá de demostrarse útil para propósitos evaluativos, también lo hace como guía para la creación de gráficos accesibles fácilmente incorporable a las guías de estilo de los medios analizados. Palabras clave

PurposeStatistical charts are an essential source of information in academic papers. Charts have an important role in conveying, clarifying and simplifying the research results provided by the authors, but they present some accessibility barriers for people with low vision. This article aims to evaluate the accessibility of the statistical charts published in the library and information science (LIS) journals with the greatest impact factor.Design/methodology/approachA list of heuristic indicators developed by the authors has been used to assess the accessibility of statistical charts for people with low vision. The heuristics have been applied to a sample of charts from 2019 issues of ten LIS journals with the highest impact factor according to the ranking of the JCR.FindingsThe current practices of image submission do not follow the basic recommended guidelines on accessibility like color contrast or the use of textual alternatives. On the other hand, some incongruities between the technical suggestions of image submission and their application in analyzed charts also emerged. The main problems identified are: poor text alternatives, insufficient contrast ratio between adjacent colors and the inexistence of customization options. Authoring tools do not help authors to fulfill these requirements.Research limitations/implicationsThe sample is not very extensive; nonetheless, it is representative of common practices and the most frequent accessibility problems in this context.Social implicationsThe heuristics proposed are a good starting point to generate guidelines for authors when preparing their papers for publication and to guide journal publishers in creating accessible documents. Low-vision users, a highly prevalent condition, will benefit from the improvements.Originality/valueThe results of this research provide key insights into low-vision accessibility barriers, not considered in previous literature and can be a starting point for their solution.

Purpose: Statistical charts have an important role in conveying, clarifying and simplifying information, and have a significant presence in fields such as education, scientific research or journalism. Despite numerous advances in the field of digital accessibility, charts are still a challenge for people with low vision and color vision deficiency (CVD) and create barriers that hinder their accessibility. The research presented in this paper aim is to create a heuristic set of indicators to evaluate the accessibility of statistical charts focusing on the needs of people with low vision and CVD. Methods: The set of heuristics presented has been developed based on the methodology by Quiñones et al. (2018), which consists of 8 stages: (1) a state of the art literature review; (2 and 3) analysis and description of the most relevant information obtained from this research; (4, 5, and 6) selection and specification of a first set of heuristics relating them to existing heuristics; (7) validation; and (8) refining the set to obtain a final list of heuristics. Results: A first set of heuristics (17 indicators) has been developed and applied on two heuristic evaluations, and has been amplified to 18 indicators. The final set covers the needs of the user profiles with low vision as well as the needs of the CVD and poor contrast sensitivity users. Conclusion: this research is a first step to widen accessibility requirements to statistical charts and to take into consideration users with low vision and CVD, often forgotten in accessibility research.

During the Covid-19 pandemic, people rely on the Internet in order to obtain information that can help them understand the coronavirus crisis. This situation has exposed the need to ensure that everyone has access to essential information on equal terms. During this situation, statistical charts have been used to display data related to the pandemic, and have had an important role in conveying, clarifying and simplifying information provided by governments and health organisations. Scientific literature and the guidelines published by organizations have focused on proposing solutions to make charts accessible for blind people or people with very little visual rest. However, the same efforts are not made towards people with low vision, despite their higher prevalence in the population of users with visual impairment. This paper reviews the accessibility of the statistical charts about the Covid-19 crisis for people with low vision that were published by the Brazilian, British, Russian, Spanish, European Union, and the United States’ governments and also by the World Health Organization and Johns Hopkins University, relating to the countries most severely affected by the pandemic. The review is based on specific heuristic indicators, with a mixed quantitative and qualitative approach. Overall, the reviewed charts offer a reasonable level of accessibility, although there are some relevant problems affecting many of the low vision profiles that remain to be solved. The main problems identified are: poor text alternatives in both, raster images and SVG charts; the incompatibility with a keyboard interface; insufficient non-text contrast against adjacent colours (in chart elements such as bars, lines or areas), no customization options; and the lack of an optimized print version for users for whom reading on screen is challenging.

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