Skip to main content

Understanding Fospha’s IQR-Based Bar Chart Capping

R
Written by Raahi Patel
Updated over 5 months ago

What it is
We’ve introduced a new visual improvement to the KPI Channel Change chart:
bar chart capping using the IQR method. This update ensures extreme values (outliers) don’t skew your dashboard—so your charts stay readable, trustworthy, and presentation-ready.


Why we introduced it

We heard your feedback: extremely high or low values in KPI dashboards were making it hard to read the charts, trust the insights, and share screenshots with stakeholders.

Our solution? A simple yet statistically sound approach to cap extreme bars using the IQR method—to keep graphs clean, readable, and insight-driven.


What’s the problem?

Outliers (like a CAC of £10,000 or a ROAS of 400x) distort your charts. That:

  • Makes it harder to spot real trends

  • Undermines confidence in the model

  • Creates messy screenshots for internal reports


What’s the fix?

We’ve applied IQR-based capping to the KPI Channel Change chart to reduce the visual impact of outliers. This ensures:

  • More consistent and readable bar sizes

  • Easier comparison across channels

  • Trustworthy visuals for your teams and execs

You'll see a tooltip ("Bar capped for scale") when hovering on capped values, and a banner so you know when capping is applied.


Why we chose IQR

IQR (Interquartile Range) is a well-established statistical method that detects extreme values while preserving the integrity of your data.

It’s the sweet spot between simplicity, accuracy, and transparency.

Pros:

  • No assumptions about data distribution

  • Works well for skewed marketing data

  • Easy to interpret and explain

What we don’t do:

  • We don’t hide or delete data

  • We don’t cap calculated metrics like ROAS or CPP directly

  • We don’t apply capping to Share of Spend or non-KPI charts


What’s in it for you?

  • Clean charts that tell a clearer story

  • Smarter screenshots for stakeholder decks

  • More trust in your marketing data at a glance


Where it shows up

Look for the update on the KPI Channel Change chart under “Channel Performance & Spend.”

Share of Spend charts remain uncapped as per your feedback.

Note: Target lines may not appear if the target value falls outside of the chart’s capped range.


Learn more

Did this answer your question?