## ACCENT Principles for effective graphical display

The essence of a graph is the**clear communication of quantitative information**. The ACCENT principles emphasize, or

*accent*, six aspects that determine the effectiveness of a visual display for portraying data.

- Apprehension:
- Ability to corectly perceive relations among variables.
*Does the graph maximize apprehension of the relations among variables?* - Clarity:
- Ability to visually distinguish all the elements of a graph.
*Are the most important elements or relations visually most prominent?* - Consistency:
- Ability to interpret a graph based on similarity to previous graphs.
*Are the elements, symbol shapes and colors consistent with their use in previous graphs?* - Efficiency:
- Ability to portray a possibly complex relation in as simple a way as possible.
*Are the elements of the graph economically used?**Is the graph easy to interpret?* - Necessity:
- The need for the graph, and the graphical elements.
*Is the graph a more useful way to represent the data than alternatives (table, text)?**Are all the graph elements necessary to convey the relations?* - Truthfulness:
- Ability to determine the true value represented by any graphical element by its magnitude relative to the implicit or explicit scale.
*Are the graph elements accurately positioned and scaled?*

Adapted from: D. A. Burn (1993), "Designing Effective Statistical Graphs". In C. R. Rao, ed., Handbook of Statistics, vol. 9, Chapter 22.