Tiles

What a tile is

One chart, number or table, reading from one report.

Choosing the right kind is most of what makes a dashboard readable. The same report drawn as a pie instead of a bar can go from obvious to useless.

The six kinds

Tile	Shows	Reach for it when	Avoid when
Metric	One large number	A single figure people watch daily	The number needs context to mean anything
Bar / Column	Groups side by side	Comparing groups	There is only one group
Line	A value over time	Showing a trend	The groups are not in time order
Pie / Donut	Parts of one whole	Three to six categories	More than about six slices
Gauge	Progress to a target	There is a real target	You have no target, only a number
Table	Rows from the report	People need the detail	It is longer than the tile

Choosing between bar and line

Both plot groups. The difference is whether the order means anything.

Line implies a sequence — it says "this followed that". Use it only when the groups are genuinely ordered, which almost always means time.

Bar makes no such claim. Use it for owners, regions, stages, anything where the order is arbitrary.

A line chart across sales reps implies a trend from Alice to Zoe that does not exist.

Why a pie with twenty slices fails

A pie asks the reader to compare angles. People are poor at that beyond a handful of segments, and the labels stop fitting. Past about six categories a bar chart is strictly easier to read.

If you have twenty categories and want a pie, the real answer is usually a bucket column grouping them into five.

Metric tiles need context

One big number is only useful if the reader knows whether it is good. "£412,000" means nothing on its own.

Give it context by using a gauge against a target instead, or by placing it beside a related metric so the comparison is on screen.

Adding one

See The dashboard builder. The short version: + Widget, choose the report, choose the kind, set the title, save.

What goes wrong

Symptom	Cause
The number is wrong	Open its report. The tile only draws what the report returns.
A chart is empty	The report has no grouping. Charts plot groups.
A table is cut off	The tile is too small, or the report returns too many rows.
The tile ignores a dashboard filter	It is unmapped. See Filters.

Where this fits

A tile is a view of a report. Change the report and every tile reading from it changes — which is a feature when intended, and a surprise when not.