2 May 2026
What a stacked bar does to a channel that shrank
A channel can lose half its spend and still look like a calm slice of the picture, if the whole season shrank with it.
Share-of-spend stacked bars are popular because they fit on one slide and they always total one hundred. That completeness is the problem. When every channel is cut, the slices can look almost unchanged. A channel that was halved is still a fifth of a smaller pile, and the bar wears the same colour as last year.
Absolute first, share second
In a campaign reading we draw small multiples of absolute spend first: one quiet column per channel, same scale, this season beside the agreed comparison. Only after that do we draw share, and the share chart is captioned with the total it is a share of. If the total fell from 1.2 million THB to 700,000 THB, that sentence sits on the sheet. The share chart is not allowed to appear alone.
The same courtesy is owed to a channel that grew only because others were switched off. Its slice gets fatter. The absolute column tells you whether anyone actually spent more. Budget meetings in Bangkok retail groups often promote the fatter slice and leave the smaller total for a footnote. We put the total in the caption, in the same size as the channel names.
A worked shape, without a client’s numbers
Picture three channels. Last season: 500, 400, and 300 thousand baht. This season: 250, 280, and 170. The middle channel’s share rises. A stacked bar congratulates it. The paired columns show every channel down, the middle one down the least. The reading we would write is about the least-bad cut, not about a winner. That sentence changes what the room funds next.
If you only have room for one sheet, choose the absolute columns. Share can be a sentence underneath. The sentence is harder to applaud by mistake.