Forget bar graphs - today it's all about sparklines

But that's not all - nothing breaks up a story like the disruptive 'Refer to Table 1', but with sparklines a few years' worth of data can be illustrated within a sentence. The result is that the reader is not burdened with the frequent tabelis interruptus in your document.

The father of sparklines is Edward Tufte, who has made a substantial contribution to the art of presenting data in its most consumable form.

A bloody example

As controlling blood glucose is one of the country's most pressing needs, let's use this as an example. The normal range is 4 - 6.5.

We could show the latest results of a patient simply as a note in the patient's file, as follows:

"Glucose 5: Everything looks good and we sent the patient on his way with the news that he has a healthy blood glucose level."

Everything looks good, but if we take the last 20 readings and illustrate them with a sparkline, we get something like this, which alludes to the fact that the level might be normal today, but has been erratic over the measured period.

Glucose 5

We can make it a little clearer when we show the latest reading as a data point:

Glucose 5

However, that tells us little of the extremes, so we put in a grey band to show the normal range:

Glucose 5

If we're interested in the frequency of cases outside the normal range (which we should be), then this sparkline works admirably. So there you have it, I can report that this patient has a normal glucose level today, however there have been three instances of hyperglycaemia (above the norm) and two cases of hypoglycaemia (below the norm), so we need to make a plan.

Very applicable to business

Although also used extensively for economic data (showing trends over time), the general business applications are as plentiful as the amount of see Table x's.

As an example, if we wanted a picture of sales figures for the year, sparklines tell a much better story than just the current month's data. (See Table 1 below). (1)

The above clearly shows that 'electronics' is a major problem. But we also get the whole enchilada on one slide (and that the electronics department better pull up its socks).

So, next time you're on your 20th bar graph. Stop. Just use the sparkline feature and head off to a real bar. The sparkline feature can be found under 'Insert' in Excel 2010. Somewhat hidden, but in the middle of the insert menu bar here:

Ref 1: Diego M. Oppenheimer. Sparklines in Excel. Series constructed by Sam Radakovitz. http://blogs.office.com/b/microsoft-excel/archive/2009/07/17/sparklines-in-excel.aspx.