SPC Pareto

The SPC Pareto panel helps you identify the most significant factors contributing to defects, downtime, or any categorical issue — so you can focus improvement efforts where they matter most.

Why SPC Pareto?

The Pareto principle (80/20 rule) states that roughly 80% of effects come from 20% of causes. This plugin makes that insight instantly visible:

• Bars sorted by impact — categories are automatically ranked from highest to lowest frequency, making the biggest contributors immediately obvious
• Cumulative percentage line — a running total overlay shows how quickly contributions accumulate toward 100%
• 80/20 threshold line — a configurable threshold line highlights where the "vital few" end and the "trivial many" begin

Built for Grafana

SPC Pareto is built using Grafana's native visualization components. This means it inherits the look, feel, and behavior you already know:

• Native theming — automatically adapts to light and dark mode
• Standard panel options — legend placement, tooltip behavior, and field overrides work just like any other Grafana panel
• Resizable statistics table — drag the splitter to balance chart and table space, just like Grafana's built-in panels
• Works with any data source — use it with SQL databases, Prometheus, InfluxDB, CSV files, or any other Grafana data source

Features

Feature	Description
Raw data support	Accepts ungrouped observations and counts occurrences automatically
Automatic sorting	Categories are ranked by frequency — no manual ordering needed
Dual y-axes	Left axis shows frequency counts, right axis shows cumulative percentage (0–100%)
Threshold line	Configurable threshold (default 80%) with horizontal and vertical reference lines
Vital few highlight	Bars beyond the threshold crossing point are visually muted, making the vital few stand out
Cumulative line	Customizable color, width, and point markers
Top N / Other grouping	Collapse low-frequency categories into an "Other" bucket to reduce noise
Value labels	Optional count, percentage, or both displayed above each bar
Statistics table	Table with category, frequency, % of total, cumulative count, and cumulative % — always in Pareto order
Standard options	Unit, decimals, and display name apply to frequency values across the axis, labels, tooltip, legend, and table
Resizable layout	Drag the splitter between chart and table to adjust the view

Use Cases

• Manufacturing quality — identify top defect types across production lines
• IT operations — rank incident categories to prioritize root cause analysis
• Customer support — surface the most common complaint categories
• Software development — analyze bug categories, test failure reasons, or build errors
• Supply chain — rank supplier issues or shipment delay causes

Requirements

• Grafana 11 or later

Getting Started

1. Install the plugin from the Grafana Plugin Catalog
2. Add a new panel and select SPC Pareto as the visualization
3. Configure a query that returns either:
   • A string field + a number field (pre-aggregated categories and counts), or
   • A string field only (raw observations — the plugin counts occurrences automatically)
4. The chart automatically sorts, calculates cumulative percentages, and renders the Pareto view

Example Query (SQL — pre-aggregated)

SELECT defect_type AS category, COUNT(*) AS count
FROM inspections
WHERE $__timeFilter(inspection_time)
GROUP BY defect_type

Example Query (SQL — raw observations)

SELECT defect_type
FROM inspections
WHERE $__timeFilter(inspection_time)

The plugin counts occurrences of each unique defect_type value automatically.

Data handling rules

• The first string field in each query result is used as the category, and the first number field (if present) as the value. If a query returns multiple number fields, reorder or remove columns so the intended value comes first.
• Query results with both a string and a number field are treated as pre-aggregated; results with only a string field are counted as raw observations. Multiple queries can be combined.
• Rows with a missing category or missing value (null, NaN) are excluded from the analysis. When rows are excluded, a note appears below the statistics table.
• Negative values are not valid for Pareto analysis. If the data contains a negative value, the panel shows an error instead of a misleading chart.

Example Query (TestData)

For a quick demo, use the TestData data source with the CSV Content scenario:

category,count
Scratch,45
Dent,38
Contamination,29
Misalignment,22
Color Defect,15
Crack,12
Burr,8
Warping,6
Porosity,4

Panel Options

Threshold

Option	Description	Default
Show threshold line	Display the 80/20 reference lines	On
Threshold value	Cumulative percentage threshold	80%
Highlight vital few	Visually mute bars beyond the threshold crossing point	Off
Trivial bar opacity	Opacity for the muted "trivial many" bars (10–100%)	40%

Cumulative line

Option	Description	Default
Line color	Color of the cumulative percentage line	Orange
Line width	Stroke width of the cumulative line	2
Show points	Show point markers on the cumulative line	On
Point size	Size of point markers	5

Top N / Other

Option	Description	Default
Limit categories	Group low-frequency categories into an "Other" bucket	Off
Show top N categories	Number of categories to show before grouping the rest	10

Bar

Option	Description	Default
Bar color	Color of the frequency bars	Blue
Fill opacity	Bar fill opacity (0–100%)	80%
Line width	Bar border width	1
Gradient mode	None, Opacity, or Hue	None
Show value labels	Display labels above each bar	Off
Label content	Count, % of Total, or Both	Count

Statistics table

Option	Description	Default
Show statistics table	Display the statistics table below the chart	On

Standard options

Option	Description
Unit	Unit applied to frequency values (y-axis, bar labels, tooltip, table)
Decimals	Number of decimal places for frequency values; when set explicitly, it also applies to the computed percentage columns (default: 1 decimal)
Display name	Renames the value series in the legend, tooltip, and table column header (default "Frequency")

Documentation

For detailed documentation, configuration guides, and examples, see the full documentation.

Part of the KensoBI SPC Suite

SPC Pareto is part of a growing family of Statistical Process Control plugins for Grafana by Kenso Software:

SPC Chart Panel — Control charts for monitoring process stability over time. Supports Xbar-R, Xbar-S, and XmR charts with automatic calculation of control limits. If you're tracking whether a process is staying in control, this is your starting point.

SPC Histogram Panel — Distribution analysis with histograms, bell curves, and a built-in statistics table showing Cp, Cpk, Pp, and Ppk. Use it to understand process capability: is your process producing results within specification limits?

SPC CAD Panel — Brings 3D geometry into the picture, letting you bind the data from control charts and histograms to physical features on your parts.

License

This software is distributed under the AGPL-3.0-only license — see LICENSE for details.

Support

If you have any questions or feedback, you can:

• Ask a question on the KensoBI Discord channel.
• GitHub Issues: https://github.com/kensobi/spc-pareto/issues