Most cluttered dashboards share the same root cause: someone picked a chart type first — because it looked good, or because it was the default — and then forced their data into it. The better order is the reverse: start with what you actually need to answer, then pick the chart built for that question.
This guide works need-first. For each common reporting question, it lists the generic chart types (the ones available in any BI tool, not tied to one vendor) that actually fit, ranked by how well they fit — and which ones to avoid even though they're popular.
Comparing Categories
"Which region sold the most? Which product line is biggest?" — comparing a handful of discrete categories against each other.
Need: Compare categories by size
Bar / column chartBest fit
The default for a reason — length is the easiest visual encoding for the eye to compare accurately.
Pie / donut chartAvoid
Angle and area are notoriously hard to compare precisely. Works only for 2–3 slices; falls apart past that.
Showing a Trend Over Time
"Is revenue going up or down? What does the seasonal pattern look like?" — anything where the X axis is time.
Need: Show change over a continuous time period
Line chartBest fit
Continuity is the point — a line makes the shape of the trend, not just the individual points, immediately visible.
Bar chartWorks, with caveats
Fine for a handful of discrete periods (quarters, years) where each bar is a meaningful unit on its own.
Finding Which Few Contributors Drive Most of a Result
"Which customers make up most of our revenue? Which defect types cause most of our quality issues?" — the classic 80/20 question.
Need: Identify the vital few contributors (80/20)
Pareto chartBest fit
Sorted bars plus a cumulative % line make the breakpoint — where the "vital few" end and the "trivial many" begin — visible at a glance.
Plain sorted bar chartWorks, with caveats
Shows the ranking, but without the cumulative line the reader has to do the 80% math themselves.
"What does a typical order actually look like? Are we dealing with one group of customers or two very different ones?" — questions about spread, not totals.
Need: See how values in a measure are distributed
HistogramBest fit
Bins the measure into ranges and shows the shape directly — skew, spread and multiple peaks are all visible instantly.
Box plotWorks, with caveats
Great for comparing spread across several groups side by side, but hides the shape (unimodal vs. bimodal) that a histogram shows.
Bar chart by categoryAvoid
A bar chart compares distinct categories — it can't show the distribution of a single continuous measure.
Start with the question, not the chart. "Compare" usually means bars. "Trend" usually means a line. "Distribution" needs a histogram, not a bar chart wearing a distribution's clothes. "Two dimensions at once" needs a heatmap, not a stacked bar straining to hold a third variable. Match the need first, and the right chart is almost always obvious.
FAQ
What chart should I use to compare categories?
A bar or column chart — length is the easiest visual encoding for the eye to compare accurately. Avoid pie or donut charts once you have more than 2-3 categories.
What chart shows the shape of a distribution?
A histogram, not a bar chart. A histogram bins a continuous measure into ranges to reveal spread, skew and whether there are multiple peaks — a bar chart compares distinct categories instead.