Data represented in graphs can be manipulated by altering the axes of the graph. There are many ways the data can be altered including:
- using different scales on graphs that are side by side
- using log scales to compress the differences
- using amputated axes to exaggerate the differences
- origins of graphs not starting at zero
By using these tricks a graphical representation of the data can be altered to make it visually more impressive. The distance between lines on the same graph can be enhanced or reduced.
Look out for enhancements where a demonstration of difference would be expected by the reader, for example in the primary outcome of a study. Look out for reductions where similarities between treatments would be expected by the reader, for example adverse effects.