Problem
A current value alone does not show the distance to a goal or whether progress is on pace.
Solution
Show the measured value against a clearly labeled target. A compact bar with a target marker can also include background ranges when those ranges have defined meanings.
Use readable labels and distinguish ranges by more than red and green alone. Show expected progress by now when the goal has a deadline.
Allow the scale to show values beyond the target when exceeding it is possible. Keep the target’s definition and review information available.
Use when
There is an agreed goal and people can act on the gap or pace toward it.
Don’t use when
The “target” is decorative. A progress bar against a number nobody committed to is a bar chart with extra implication, and it teaches viewers to ignore the ones that matter. Also don’t use it when the metric has no meaningful ceiling; progress toward infinity is just a value.
Trade-offs
A progress bar can hide how quickly the value is changing. Old targets may become irrelevant, and visible goals can encourage optimizing the metric at the expense of the real outcome. A full bar should not imply a maximum unless one exists.
Checklist
- Who set this target, when, and is it still the right one?
- Is expected progress by now shown, or only progress to date?
- What happens visually past 100%, and is overshooting good here?
- Are the qualitative bands encoded as intensities of one hue rather than red/amber/green?
- Would a colorblind reader get the same reading as everyone else?
- Is the target a line the eye can locate precisely, or a color boundary it has to estimate?
- Does the bar start at zero, and if the range doesn’t, is that labelled?
- Is the underlying number visible, or only the proportion?
- If this is a budget being consumed, does the display show burn rate as well as balance?
- What does it show before the period starts, and after it ends?
Compare
Grafana’s bar gauge is the closest thing in the category and stops short of a bullet graph: thresholds color the bar itself rather than sitting behind it as ranges, so the qualitative context and the measure share one channel instead of two. Honeycomb frames the same pattern as error budget rather than progress, showing what’s left and how fast it’s going, which answers the pace question the generic progress bar drops. Tableau ships Few’s bullet graph as a built-in, which is why it’s the version most analysts have actually seen. Netdata largely skips targets, on the position that a per-second chart with a threshold line already says everything a progress bar would.
Related
Gauge is a radial alternative for a bounded range. KPI tile emphasizes the value. Metric targets defines and maintains the goal.
Threshold line places the reference on a time chart. Semantic status color supplies consistent state cues.