# Displaying prices, where lower is better, in a graph

When displaying prices (where lower prices are better) in a chart, should the lower price be at the top or bottom?

I'm asking, because usually higher placement = better result, but it's counter-intuitive for lower numbers to be at the top of a graph.

A similar issue exists on horizontal layouts as well (right is better, yet lower numbers are on the left).

• What about (i) plotting profit instead of price, or (ii) using a reverse y scale? May 5, 2014 at 0:40
• When charting data, it's really hard to answer specific questions like this without having a much broader understanding of the context. Can you post an example of your data? What is important, the price, or change in price? Who's the audience? etc...
– DA01
May 5, 2014 at 20:48

Definitely put in an increasing Y axis, so that the lower prices are at the bottom. User's aren't THAT unintelligent that they won't quickly figure out what they're seeing, when looking for something that's cheap it's logical to look for the lowest points on a graph.

By reversing the axis and placing the lower values "higher" up you'll create a lot of confusion and frustration because users expect an ascending axis, never a descending one. I've attached two graphs with the two types of axes I think you're describing - for me personally it's MUCH easier to read the second instead of the first.

If you change the measure to being "Best Value" (i.e. price-per-item) then this would not only provide a graph with the "optimistic" shape, but could also be a better cognitive match with what your user is actually looking for.

However if all the inverted measures you can come up with are "unnatural" (have significant cognitive dissonance) then you will create a bigger issue.

In this case the alternative solution would be to highlight "what good looks like" e.g.

download bmml source – Wireframes created with Balsamiq Mockups

You could use an upside-down graph, where you plot the prices as their negatives (just don't label them as such), thus, the lower the price, the closer it would be to the top (the 0-line) and the higher the price, the further away from the 0-line it would be.

E.g.

I'm not sure of the type of graph you are going to be using (showing a solid price, or a price change over time), but the theory behind my answer would work in either case.

You can use colour to indicate which is the better option, here is an example of what I mean.

The same idea of using colour and clear labels would work in a bar graph or something similar also.

I'd advise against inverting the Y axis, it was done recently and cause a lot of confusion among readers and many of which were mis-understanding the data.

I think that there are so many charts and graphs available in the world, that there is certainly one that will suit your needs. Try to consider charts that are circular in nature, such that they have no highs or lows.

• This doesn't really provide an answer though. You're basically just saying - do some research, which is what OP is doing by asking this question in the first place. Can you explain what you mean by 'circular charts' in this context?
– JonW
May 8, 2014 at 13:47
• I'm trying to give an example of a type of chart that eliminates the problem OP is having, which is the vertical placement of chart elements. I think there is a creative opportunity here to tackle a interesting problem in data presentation. That said, I think OP needs to provide some more context about his data to allow for more complex answers. May 8, 2014 at 14:44