Fixing/standardizing scatter chart marker size

[dmd1]

Hi, 

I have multiple scatter charts on the same page, all drawing from the same table (table is called 'output').

Marker size is determined by the count of points at that position. 

However, the maximum number of points in the same position varies across the scatter charts, so a count of 2 in the left chart (e.g. the top blue dot) produces a marker the same size as a count of 5 in the right chart (e.g. the blue dot in the middle).

(Marker size settings (Range scaling and Size) are the same for both charts).

How can I set the marker size so that:

1) e.g. a count of 2 points will be the same size in every scatter chart, and 

2) marker size will be invariant to any filtering applied to any scatter chart (so a marker for a count of 2 should remain the same size no matter what)

Things I have tried:

- a bunch of measures like 

Size = CALCULATE ((COUNT(output[UID])^4), REMOVEFILTERS(output[Opp], output[Int], output[Ext], output[UID]))

Size = CALCULATE ((COUNT(output[UID])), REMOVEFILTERS(output))

- putting 10 white/invisible dummy points in a corner of each visual to standardise the max count of points in each scatter plot (this helped, but the sizing went weird when filtering was applied).

Thanks in advance for your help!

[Ritaf1983 · Accepted solution]

Hi @dmd1 

Hi,

There’s currently no built-in way in Power BI to “freeze” the marker size across multiple scatter charts — marker size is always relative to the maximum value of the size measure within that specific chart. So even if both visuals use the same settings, a count of 2 might appear different depending on the chart’s internal scale.

However, here are two solid alternatives:

 Option 1: Use a Ranking Measure Instead of Raw Count
Instead of using the raw count for the marker size, you can create a ranking measure (e.g., 1–10) based on the count of points in each position. Then use that rank as the size field in the scatter charts. This way, a Rank of 2 will look the same size across all charts — assuming the rank scale is identical across visuals.

But keep in mind:

You still can’t lock the marker size to an absolute value (e.g., "2" will always be size 15).

You cannot freeze a single value’s marker size across filters — Power BI always rescales marker size based on what’s visible.

Option 2: Add Ranking or Summary Charts Next to the Scatter
If your primary goal is to compare values across charts, especially when using the scatter as a spatial layout (like your triangle format), consider adding bar charts or tables next to the scatter to show ranking, count, or totals directly.

People are not good at visually comparing circle sizes, especially when the difference is subtle.

Scatter plots are among the most cognitively demanding visuals, because they encode three or more variables (X, Y, color, size).

Trying to assess size differences based on dot radius leads to misleading interpretations — and breaks down completely when switching filters or visuals.

So from both a data-visualization and user-experience perspective, pairing the scatter with clear, ranked visuals is far more effective for comparison — as shown in the screenshot example.

If this post helps, then please consider Accepting it as the solution to help the other members find it more quickly.