The sales candle
Why we show sales like a share price – and what one candle tells you about a day.
“Was June good?” The honest answer is almost always: it depends what you compare it with. Growth against a weak June last year is something different from growth against a normal one. And a line pointing upwards says nothing about whether it rises steeply enough.
That is why Pythia shows sales not as a line but as candles – like a share price. With a different meaning, though.
One candle, two numbers
On the stock market a candle shows a day’s open, close, high and low. In Pythia it means something else:
- Open is the expectation: what would normally have been sold in this period.
- Close is the actual: what was really sold.
- The body in between is the deviation. Its colour tells you whether we were above or below expectation.
- The wick is reserved for a corridor that later comes from several previous years.
So no second curve is needed to compare expectation and actual. A long red body deserves a question. A short body means: close to expectation, even if the number is smaller than last year.
A line shows what happened. A candle shows whether it was a surprise.
The right resolution on its own
How fine a candle is depends on the selected period. For windows of up to 70 days Pythia shows daily candles, beyond that weekly and monthly ones. Nobody has to set a granularity – a click on a candle zooms in, and the candles get finer.
The figure can be switched: revenue, units, lines or margin. The tooltip on every candle gives actual, expectation and deviation.
A candle without an actual
Because Open and Close are separate, a candle can also consist of an expectation alone – as a dashed line. That is the basis for the timeline later reaching beyond the last day of data.
Why Open matters today
A real forecast is a later stage of Pythia. But the candle needs its Open now. So it starts with a simple, traceable expectation from previous years. When a forecasting model is added later, only the source of the Open value changes. The candle itself, its meaning and everything people have learned to read from it stay the same.
Next month: data that arrives on its own – why nobody has to upload files any more.