Callouts: Make the Point

What a callout is

The box beside the chart that answers "so what?"

A callout is a short block of text placed next to a chart. It holds the part of the message the chart can't show: why the finding matters and what the reader should do about it.

Consulting slides from firms such as McKinsey, BCG and Bain put a takeaway box beside the exhibit for exactly this. Cole Nussbaumer Knaflic, in Storytelling with Data, says the same thing in plainer terms: put the takeaway into words, so the audience doesn't have to work it out.

Presentation page titled Production loses 40% of its staff, three times the rate in Sales. A bar chart of turnover by department with Production in blue, and a callout beside it: Start retention work in Production. It holds 208 of 301 staff, so it accounts for 83 of the 102 people who left. A blue line joins the callout to the Production bar. — Title, chart and callout each do one job. The callout adds two numbers the chart doesn't show (208 staff, 83 exits) and ends in an action.

Part	Its job	In this page
Title	The finding	Production loses 40% of its staff, three times the rate in Sales
Chart	The proof	Turnover by department, Production in the accent
Callout	The implication and the action	Start retention work in Production: it holds 208 of 301 staff and 83 of the 102 exits

When to use one

A presentation page that makes one point.

A callout earns its place when the page shows one fixed view and has one message to land:

A presentation or read-ahead page. When the report is sent rather than presented, the callout says what you would have said out loud.
The insight goes beyond the chart. A cause, a cost, a share of the total, or the decision it points to.
There is an action. If you can't name one, the page may not need a callout. A good title may be enough.

It doesn't earn its place on a dashboard where filters change the numbers, or when it only repeats the title. Both are shown next.

One callout per page, beside the main chart. If a page needs three callouts, it has three messages. Split it.

Not on dashboards

A filter can make typed text false.

A dashboard has slicers. A callout typed for the full company stays the same when the reader filters, even if the chart underneath no longer agrees.

Below, the reader has picked IT/IS. The callout still talks about staff under $20 an hour, but IT/IS has nobody in that band. And within IT/IS the $45+ band loses more people (26%) than the $30 to $44 band (19%).

Dashboard filtered to IT/IS. The chart shows turnover by pay band: $20 to $29 33%, $30 to $44 19%, $45+ 26%. The typed callout below still says Lower pay, higher turnover: staff under $20/hr leave at 40%, twice the 20% rate of those on $45+. — The callout describes a bar that isn't on screen. The reader stops trusting the page.

Same dashboard with a callout that reads IT/IS: 24% left, 10 points below the company rate of 34%, and a smaller line saying Filtered to: Department = IT/IS. — The sentence is calculated, so it is true for whatever the reader selects. It names the filter and stays to one line.

On a dashboard you have three safe choices: no callout, a callout that only defines terms ("Turnover = people who left / all employees"), or a short sentence built from a measure. The build steps are in In Power BI.

Don't repeat the title

If it says what the title says, cut it or make it add something.

The most common weak callout restates the title or the chart. The reader has already seen both, so it costs space and tells them nothing. The fix is to ask: what does the reader need to know that this chart can't show?

Presentation page titled Exits nearly doubled in 2015, to 26 from 14, with a line chart of exits per year. The callout says Exits rose sharply in 2015. They went from 14 in 2014 to 26 in 2015. — Same numbers, same claim, a third time. The reader learns nothing new.

Same page. The callout says Find out what changed in 2015. Terminations rose from 2 to 5 and resignations from 12 to 21. 2016 had 14 exits by June, already matching all of 2014. — It splits the rise by type and flags that 2016 is on the same pace. Then it says what to do.

Lead with the action

Put the implication first, not a description of the chart.

Start the callout with the thing the reader should do or conclude, in bold. The evidence follows. A callout that opens with "This chart shows" is a caption, and the chart already shows it.

Poor~~This chart shows turnover by department.~~Describes the chart. Adds nothing.

OkayProduction has the highest turnover.A finding, but the chart and title already say it.

ExcellentStart retention work in Production: it holds 208 of 301 staff and 83 of the 102 people who left.An action first, then two numbers the chart doesn't show.

BeforeA caption in a box

It tells the reader what they are looking at, which they can already see.

Same page. The callout says Grow referrals before paid sources. Referrals cost $0 in the recruiting budget and brought in 31 hires. The Diversity Job Fair costs $10,021 a year, and 16 of its 29 hires have left. A blue line joins it to the Employee Referral bar. — Bold action first. The cost numbers come from the recruiting budget, so they add something the turnover chart can't show.

Quantify it

"Many" and "some" are not findings.

Vague words make the reader guess the size, and the guess is usually wrong. Give the number and what it's out of. If you write an action, make it specific enough that someone without the data couldn't have written it.

Presentation page titled Another job or more money explains 30% of exits, with a bar chart of the top 8 reasons for leaving. The callout says Retention is a concern. Many employees seem to leave for better opportunities. HR should consider ways to improve retention. — "Many", "seem", "consider ways": nothing to check and nothing to do.

Same page. The callout says Ask about pay and next roles in stay interviews. 31 of the 102 people who left went for another position or more money. Another 14 said they were unhappy, a reason a stay interview can catch early. — Counts with their base (31 of 102), a named action, and a third reason the chart only hints at.

Keep it short and close

A few lines, right next to the evidence.

The reader's eye moves from the chart to the nearest text. A paragraph at the bottom of the page is read last, if at all. Keep the callout to a bold first line and one or two short sentences, under about 40 words, and put it beside the bar it is about. If a page needs more words than that, the chart isn't doing its job.

Presentation page titled Production staff resign at 36%, the highest rate of any department, with a bar chart and a long paragraph underneath that walks through every department's rate and ends by saying further analysis may be needed. — It reads the chart back bar by bar, hedges, and ends with no action.

Same page with a short callout to the right of the chart: Start exit interviews in Production. 75 of 208 resigned, 7 points above the company rate of 29%. A thin blue line runs from the callout to the Production bar. — Two sentences next to the bar they explain. When the box sits beside the chart, a thin accent line makes the link explicit.

Tie it with colour

Use the chart's accent in the callout, and nothing else.

Knaflic ties words to data with colour: the key number in the text takes the same colour as the bar it describes, so the reader links them without looking for a legend. Three small touches do it:

A thin accent rule down the left edge of the box.
The key numbers in bold accent, the rest of the text in dark grey.
Optionally, a leader line in the accent from the box to the bar.

A second colour in the text, or a heavy border around the box, breaks the link and pulls the eye away from the chart.

Presentation page titled Staff paid under $20 an hour leave at twice the rate of those on $45+. The Under $20 bar is blue, but the callout numbers 71 of the 72 and 40% are orange, inside a heavy black border. — Orange suggests a second category that isn't on the chart. The black frame is the loudest thing on the page.

Same page. The callout has a thin blue rule on the left, the numbers 71 of the 72 and 40% in bold blue, and a blue leader line to the Under $20 bar. It says Review Production pay first. 71 of the 72 staff under $20/hr work in Production, and 40% of that band have left. — Bar, rule, numbers and line share one blue. The callout also says why pay points to Production: almost everyone under $20 an hour works there.

The checklist

Check	Ask yourself
Leads with the action	Is the first line, in bold, what the reader should do or conclude?
Adds something	Does it say something the title and chart don't?
Quantified	Does every claim have a number and a base ("31 of 102")?
Short	A bold line plus one or two sentences, under about 40 words?
Close	Is it beside the bar or point it describes?
Same accent	Do the key numbers share the colour of the data they describe?
Still true	On a page with slicers, does it update, or does it need to go?

In Power BI

A text box, two shapes and, on dashboards, a measure.

Write the callout in a text box

Insert > Text box. Place it beside the main chart, top-aligned with it.
Type the action line, select it and set it to bold, about 14-16 pt. Type the evidence below at 12-13 pt in dark grey.
Select each key number and, in the text box toolbar, set Font color to the accent hex (here #2A78D6) and bold.
In Format text box > Effects, set Background to white or off, and turn Visual border off.

Add the accent rule and leader line

Insert > Shapes > Rectangle. Make it 4 px wide and as tall as the text box. Set Fill to the accent and turn the Border off. Place it on the box's left edge.
Insert > Shapes > Line. Set the line colour to the accent, width 1-2 px, and run it from the box to the end of the bar.
Select the text box and both shapes, then Format > Group so they move together.

Make the bar match the callout

Create a colour measure: Bar Colour = IF ( SELECTEDVALUE ( Employees[Department] ) = "Production", "#2A78D6", "#C8C6C4" )
On the chart, open Format visual > Bars > Colors, click fx, choose Field value and pick Bar Colour.

On a dashboard: build the sentence from a measure

Create a text measure like Callout Text below. It reads the current filters every time a slicer changes.
Either insert the Narrative visual (called Smart narrative in older versions), type your sentence, and use + Value to drop measures into it; or add a Card, put Callout Text in it, turn the category label off and turn on word wrap.
Add a second, smaller measure that names the active filter, so the reader knows what the sentence describes.

Callout Text =
VAR Rate    = [Turnover Rate]
VAR Company = CALCULATE ( [Turnover Rate], REMOVEFILTERS ( Employees[Department] ) )
VAR Gap     = ( ROUND ( Rate, 2 ) - ROUND ( Company, 2 ) ) * 100
VAR Dept    = SELECTEDVALUE ( Employees[Department], "These departments" )
RETURN
    IF (
        ISBLANK ( Rate ),
        "No employees match these filters.",
        Dept & ": " & FORMAT ( Rate, "0%" ) & " left, "
            & FORMAT ( ABS ( Gap ), "0" ) & " points "
            & IF ( Gap < 0, "below", "above" )
            & " the company rate of " & FORMAT ( Company, "0%" ) & "."
    )

Filter Note =
IF (
    ISFILTERED ( Employees[Department] ),
    "Filtered to: Department = "
        & CONCATENATEX ( VALUES ( Employees[Department] ), Employees[Department], ", " ),
    "All departments"
)

Keep the dynamic sentence short. One sentence, one comparison. Every extra clause is another place a filter can produce a blank, a "0 points above", or a claim that reads oddly. Round the numbers before you compare them, so the sentence never says "9 points" between 24% and 34%. Handle the blank case, and test the measure with each slicer value before you publish.

Test your eye

Rewrite these before you open the answer.

A callout reads "This chart shows the share of employees who left in each department." What's wrong, and what would you write?

It describes the chart instead of saying what it means. Lead with the action and add what the chart can't show: "Start retention work in Production: it holds 208 of 301 staff and 83 of the 102 people who left."

The title says "Referral hires stay: only 13% left, against 34% overall". The callout says "Referral hires have much lower turnover than average." Keep it?

No. It repeats the title with vaguer words. Either cut it, or make it add something: the cost ("Referrals cost $0 in the recruiting budget") and an action ("Grow referrals before paid sources").

An HR dashboard has a Department slicer and a typed callout: "Production loses the most people." Is that safe?

No. Once a reader selects any other department, Production isn't on screen and the sentence is wrong. Remove it, or build the sentence from a measure that names the current selection.

The chart's highlighted bar is blue. The callout's key number is in red, inside a thick black box. What would you change?

Make the number the same blue as the bar, drop the black border, and use a thin blue rule on the left edge instead. Red also suggests "bad", which is a second message the chart doesn't carry.

A callout runs to 120 words at the bottom of the page. Where do you start cutting?

Cut every sentence that reads a bar back to the reader. Keep the one implication and the action, put it in bold as the first line, add the one or two numbers that support it, and move the box beside the bar it's about.

Say what it means. Then say what to do.