Combo Charts in Sigma: How They Work and When to Use Them

Yes. Sigma supports combo charts, which combine visual forms such as bars and lines in one chart so you can compare measures that share a category or time axis. They are useful for questions such as how monthly sales relate to a target, but they need careful axis and series choices to avoid a misleading comparison.

What a combo chart means in Sigma

Sigma is a cloud-based analytics and business intelligence platform, and its chart elements turn data from a workbook into visualizations. A combo chart puts two or more series in the same plotting area while allowing series to use different mark types. A common arrangement is bars for a quantity and a line for a rate, target, or trend. The shared horizontal axis makes it possible to compare the series across the same dates, products, regions, or other categories.

The word combo describes the visual construction, not a particular analysis. The chart does not automatically establish that two measures are related or that one causes the other. The reader still needs to know what each series measures, what its units are, and whether the scales make the comparison fair.

In Sigma, you generally configure the chart element from the workbook’s chart settings: select the chart, choose a combo-style visualization when available, then configure the measures and their display. The names and layout of settings can change as Sigma updates its interface, so use the chart configuration panel shown for your workspace rather than relying on a fixed sequence of clicks.

When a combo chart is useful

A combo chart is most useful when a reader needs to compare two different kinds of information that line up on one category axis. Bars are effective for showing amounts by period, while a line makes a target or rate easy to follow. For example, a retail dashboard could show monthly revenue as bars and gross margin percentage as a line. A service team might show weekly ticket volume beside the share of tickets resolved within a service-level target.

It can also help distinguish actual performance from a reference value. A bar series can show actual units sold while a line shows a monthly target. If both measures use the same units and scale, the line can make it straightforward to see which periods exceeded the target.

Amounts plus rates: orders and conversion rate by week.
Actuals plus a target: completed projects and a target count by month.
Volume plus a quality measure: calls handled and average satisfaction score by team.

Use one only when the measures have a meaningful shared axis and the audience benefits from seeing them together. If the series have unrelated categories, or the chart becomes crowded, separate charts are often clearer.

How to build one in a Sigma workbook

Start with the data and question, not the chart style. Confirm that the source contains a useful category field, such as a date, product, or region, and the measures you want to compare. For a monthly trend, the data should have a date field that can be grouped consistently by month and numeric fields for each measure. Check that the chart’s aggregation matches the question: a sum of revenue answers a different question from an average order value.

Add or select a chart element. In the workbook, use a chart based on the relevant data element, or select an existing chart to edit it.
Set the category axis. Choose the date or category field that both series should share. For dates, use a sensible time grouping so the chart does not show an unreadable point for every raw timestamp.
Add the measures. Include the numeric fields that answer the comparison question. Verify their aggregations and filters before styling them.
Choose the combo presentation. Use the chart type or series settings to combine marks, commonly bars for one measure and a line for another. Assign the mark type to each series where Sigma’s configuration provides that option.
Review axes and labels. Set appropriate number formats, identify units, and decide whether measures need separate scales. Check the result at the size and level of detail where people will actually view it.

The precise controls available can depend on the chart configuration and product changes. If you do not see a combo option, check whether the selected chart type, number of measures, or current workbook setup supports it, and consult Sigma’s current product documentation. Do not assume that every chart supports every combination of marks or axis settings.

Choosing measures and chart types

Pick marks according to what the data represents. Bars are usually suitable for discrete comparisons such as revenue by month or cases by department. Lines work well for ordered sequences, especially time, because connecting the points suggests continuity. A line over categories such as unrelated product names can imply a progression that does not exist. If the category order is meaningful, make that order explicit.

Keep the chart focused. Two series are often enough; adding many measures can make the legend difficult to interpret and can bury the main signal. Name each series in plain language, and avoid labels such as Metric 1 when a reader needs to know whether the value is dollars, units, a percentage, or a score. If one measure is a target, label it as a target rather than presenting it as another actual result.

Also check that the aggregation is appropriate for each measure. Summing a percentage across rows is generally not a meaningful way to calculate an overall rate. The correct calculation may require a ratio of totals or a weighted average, depending on how the source data is structured. Resolve that in the data model or calculation before relying on the visual.

Using a second axis without misleading readers

A major reason to combine measures is that they use different units or magnitudes. Revenue might be in thousands of dollars while margin is a percentage. If both are plotted against a single scale, the smaller-valued measure may look flat. A secondary axis can make both series visible, but it also creates a design risk: the apparent crossing or closeness of the line and bars can change when either scale changes.

Use a secondary scale only when it is necessary and clearly labeled. Include units in axis titles or series names, such as Revenue ($) and Margin (%), and make the legend unambiguous. Do not use the visual distance between a bar top and a line point as evidence that the measures are numerically close when they use different axes. For targets expressed in the same units as actuals, a shared axis is usually easier to interpret.

When the chart is meant for a broad audience, consider whether two aligned charts would communicate the comparison more honestly. The reader can still compare the timing without having to interpret two scales in one plot.

Example: sales and conversion rate

Imagine an online store reviewing performance across six months. It has monthly order revenue and conversion rate, defined as orders divided by visits. A combo chart could display revenue as columns and conversion rate as a line, with month on the horizontal axis. The bars answer how much revenue was generated in each month; the line shows whether the share of visits that became orders changed.

Before drawing conclusions, the analyst should confirm that the conversion rate is calculated from the underlying totals, rather than averaging daily percentages without weighting. They should also check whether changes in traffic mix, promotions, or product availability could explain the pattern. If revenue rises while conversion falls, the chart shows that both occurred in the same months; it does not by itself explain why.

A useful dashboard adds context in the title or subtitle and uses clear units. For instance, a title can identify the period and population, while a note explains that conversion rate is orders divided by visits. If the audience needs exact values, data labels or a detail table may help, but labeling every point can clutter the chart.

Common problems and ways to fix them

The line looks flat. The series may have a much smaller range than the bars. Confirm that the units are correct; if they genuinely differ, consider a clearly labeled secondary axis or separate charts.
The chart changes dramatically when filters change. Check whether the axis automatically rescales. A changing scale can be valid, but it makes comparisons between filtered views harder. Use a consistent range when the comparison requires one and the chart settings allow it.
Dates appear out of order. Make sure the horizontal axis uses a date field or a deliberately sorted time category, rather than text labels that sort alphabetically.
The line jumps between categories. Confirm that connecting the categories makes sense. A line can imply continuity; for unordered categories, bars or points may be more suitable.
The chart is hard to read in a dashboard. Reduce the number of series, strengthen the legend and axis labels, and check the chart at its published size. A design that works when enlarged may become unclear in a compact tile.

Finally, inspect filters and data freshness. A combo chart can be visually polished while still reflecting an unintended filter, an incomplete period, or an unexpected null value. Validate a few displayed values against the underlying table before sharing the dashboard.

Combo charts versus separate charts

A combo chart saves space and makes it easy to compare timing, but it asks the reader to interpret multiple mark types and sometimes multiple scales. Separate charts are preferable when the units are very different, when the series have different category axes, or when each measure needs a detailed view of its own. A small-multiple layout can preserve a shared time axis while giving each measure its own scale.

A table is better when exact values and direct row-by-row comparisons matter more than visual patterns. A single line chart is often better for several trends with comparable units, and a bar chart is often better for comparing categories at one point in time. The right choice is the simplest view that answers the reader’s question without hiding important differences.

Frequently Asked Questions

Does Sigma have combo charts?
Yes. Sigma provides combo-style charting for combining visual forms such as bars and lines. The available series and axis controls depend on the chart configuration in the current product interface.

Can I put a line and bars on the same Sigma chart?
That is a common combo-chart setup. Add the relevant measures to the chart and configure the series to use the appropriate mark types, if those controls are available for the selected chart.

Can a Sigma combo chart use two y-axes?
Axis options can depend on the chart setup and current Sigma interface. If a secondary axis is available, label both scales clearly and avoid treating visual alignment across different units as a numeric comparison.

Why is my line not visible?
Check whether its values are being plotted on a scale dominated by another measure, whether the series is included and filtered as expected, and whether its mark type and formatting make it distinguishable. A separate or secondary scale may help when the units differ.

When should I avoid a combo chart?
Avoid it when the measures do not share a meaningful category axis, when the second scale could mislead, or when the chart becomes too crowded. Two aligned charts or a table may communicate the data more clearly.

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