Make the First Choice
| Question or detail | Chart | What to check |
|---|---|---|
| When did one or several values rise or fall? | Line Chart | Ordered observations and comparable units; add series to compare multiple paths. |
| How large was the quantity through time? | Area Chart | A filled region from the series to a meaningful baseline. |
| How did components contribute to the changing total? | Stacked Area Chart | Nonnegative components that can be added at each observation. |
| What were the open, high, low, and close? | Candlestick Chart | One ordered session per date, with open and close inside the low-to-high range. |
| When do tasks start, end, and overlap? | Gantt Chart | Distinct task IDs and start/end dates with an explicit end-boundary rule. |
| How do a few separate periods compare? | Bar Chart | A distinct total for each period, with a zero baseline. |
WORKED EXAMPLE / ILLUSTRATIVE DATA
Follow a Weekly Support Queue
A fictional support team records unresolved tickets at the same time each Friday. These are snapshots of a queue, not the number of tickets received during the week.
| Week | Unresolved tickets |
|---|---|
| Week 1 | 40 |
| Week 2 | 55 |
| Week 3 | 35 |
| Week 4 | 30 |
A line highlights the Week 2 peak and subsequent decline. Filling to zero can emphasize the queue size. Adding the four values would not tell you how many unique tickets were handled, because a ticket can appear in multiple snapshots.
Separate a Path From a Stack
The Line Chart editor can add several series while preserving one value per series and row. Use these paths to compare individual changes. Stacked Area instead adds nonnegative components so its upper boundary shows the total at each observation. Only its bottom band has a fixed baseline.
Do not stack unrelated rates or averages just because they share a unit. Check whether the components describe non-overlapping parts of the same total. A fill is not a cumulative sum over time.
Match Sessions and Intervals to Their Data
Candlestick keeps opening, highest, lowest, and closing values for each session. Body color compares that session's close with its own open, not with the previous close. The example uses equal spacing for recorded sessions, including when dates are skipped.
Gantt uses elapsed calendar time. The ChartTypes example includes the start date and excludes the end date, so 6 to 9 January spans three days. Weekends count. Its bars show scheduling and overlap, without implying dependencies, completion percentages, or resource capacity.
Make Time Spacing Honest
Sort observations by time before connecting them. If one observation is a day later and another is a month later, a true time scale should show that difference in spacing. Equally spaced category labels can hide irregular gaps. The ChartTypes Line, Area, and Stacked Area editors use ordered labels at equal spacing; they do not parse those labels into elapsed dates.
Choose a consistent reporting interval. A partial month needs a label or separate treatment when placed next to complete months. Otherwise a low final point may simply mean the reporting period is unfinished.
Treat Missing Values as Missing
An absent measurement is not automatically zero. Show a gap or explicitly describe any interpolation. Smoothing also creates a curve between measured points; use it only when that shape is a reasonable aid to reading.
For several series, start with lines and direct labels where space permits. Overlapping fills can obscure the lower series. Stacking is a separate choice and is meaningful only when the components can be added.
Before You Publish
- Check whether horizontal spacing represents ordered labels, recorded sessions, or elapsed time.
- Define whether values are snapshots, period totals, or rates.
- Keep time order and spacing clear.
- Explain missing periods and the vertical baseline.
Explore Working Examples
Open a chart to inspect its sample data and compare code in six libraries.