Truncating error bars in publication graph? I am preparing a graph for publication: it has 3 panels, and two groups (line graphs) in each panel, with error bars at each time point.
For one of the panels, the last time point (with fewer observations) has quite wide error bars. 
Is there a hard and fast rule about the range of the y-axis? 
Anything to cite to say one way or the other?
I can extend the range of the y axis to make sure the upper limit is included, but then it squashes the bulk of the data points together and doesn't really display the main trend of the bulk of the graph well. 
It's not about manipulating peoples views; it's about accurately portraying the (vast majority of the) section of interest as opposed to ensuring all points are included.
 A: The only place I can think of where "error bars" (better to use confidence limits and specify the confidence level) are out of control is where they should have been shown on the log scale but weren't.  For example, if one is estimating hazard ratios, odds ratios, risk ratios, or fold-change, it is more appropriate to use a log scale when presenting the point estimates and confidence limits.  This will also prevent wild limits from re-scaling the graph in way that obscures the region of interest. 
A: Options I'd consider


*

*Show the error bars fully

*Don't show error bars at all; show error some other way or not at all

*As suggested above, use log scale, if appropriate

*Delete the last time point (and explain why in the text)


I would not  truncate the error bar. To me, that does distort the data (unintentionally, but still). The fact that that last time point is estimated very badly is part of the data. 
A: We may be able to find some guidance in particular situations, but hard and fast rules are unlikely. Even if someone suggested them, we would be sure to find an exception. The only guidance I have seen about the subject is in LeLand Wilkinson's The Grammar of Graphics. Wilkinson suggests that plots of distributions, even if summarized by error bars, should always contain the full range of the data in the axis. I suspect the motivation for this should be fairly intuitive.
You give on its face a reasonable exception though (Wilkinson's suggestion was more so in the context of default behavior of graphics as opposed to any rule). Alternatives (I can think of) besides truncating the error bar is to consider separate panels in which the axis length varies between panels, or simply two plots (one zoomed out and one zoomed in). Regardless of how you handle the situation, the graphic and the text should be clearly annotated so no confusion arises. 
