quantitative-analysis

quantitative-analysis is a skill for Claude Code from cbrock84/headcount. It costs 95 tokens per session (961 once invoked), scanned A, original, MIT.

A method for answering business questions with data by defining the decision first, choosing a fair comparison, and checking whether the data supports the conclusion.

In plain words
What is it for?
It is for evaluating changes, comparing customer groups or time periods, checking metrics, and deciding whether evidence supports a business action.
Why use it?
It helps avoid confident answers built from misleading data or unsuitable comparisons, such as survivorship bias or regression to the mean.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the data-analytics plugin — 7 skills shipped together

About the project

headcount is an organization of independently installable Claude Code plugins, each grouping skills for a department such as finance, security, or demand generation. Claude Code users install the departments they need and invoke their skills for specialized work; the catalogue entries are skills and related agent tooling from that organization.

cbrock84/headcount · 1,247 stars · on GitHub · cbrock84.github.io

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/cbrock84/headcount/quantitative-analysis
Any agent
npx skills add cbrock84/headcount --skill quantitative-analysis
Clone the repo
git clone --depth 1 https://github.com/cbrock84/headcount

Made for: Claude Code.

Or install data-analytics, the plugin that ships this one along with the rest of its 7 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for quantitative-analysis

README.md
[![agentmods](https://agentmods.dev/badge/skills/cbrock84/headcount/quantitative-analysis.svg)](https://agentmods.dev/skills/cbrock84/headcount/quantitative-analysis)
Your own site
<a href="https://agentmods.dev/skills/cbrock84/headcount/quantitative-analysis"><img src="https://agentmods.dev/badge/skills/cbrock84/headcount/quantitative-analysis.svg" alt="Measured on agentmods" height="20"></a>
Per session 95 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 961 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00095 $0.00961
Opus 5 $0.00048 $0.00481
Sonnet 5 $0.00019 $0.00192
Haiku 4.5 $0.00010 $0.00096

Measured 2d ago against content hash a95b1f686c47, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

quantitative-analysis scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/data-analytics/skills/quantitative-analysis/SKILL.md · 84 lines

How it starts

The opening of the file, as written. The whole thing — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Quantitative analysis

A wrong answer here is rarely an arithmetic error. It is a correct calculation on the wrong comparison, or on data that does not mean what the field name suggests.

Frame the question so that an answer changes something

Start from the decision. "How is retention doing" has no answer; "is the cohort we changed onboarding for retaining better than the one before it, enough to justify rolling it out" does.

Write down what you expect to find and what you would do in each case before you look. If every possible result leads to the same action, the analysis is not worth running — and knowing that in advance is worth more than the analysis would have been.

Choose the comparison before the metric

Almost every meaningful number is a comparison, and the choice of what to compare against does more work than the calculation.

  • Against what it was — needs a period long enough to see through seasonality and noise.
  • Against what it would have been — the strongest comparison and the hardest to construct. A holdout group, a matched segment, a pre-trend extended forward.
  • Against a peer or a benchmark — only useful if the definitions genuinely match, which they usually do not.

Name the counterfactual explicitly. "Revenue rose after the campaign" is a comparison against nothing, and it is the single most common way credit is claimed for a trend that was already happening.

Interrogate the data before you trust it

Look at the raw rows. Check when collection started and whether the definition changed partway. Check null rates, duplicates, and test or internal accounts still in the set. Check whether recent periods are still filling in — partial data at the tail is what produces the "sudden decline" that resolves itself a week later.

A field's name is not its definition. Find out what actually writes it and under what conditions, especially for anything named status, type, active, or created.

Know the traps that produce confident wrong answers

Read the full file on GitHub · 84 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 84 lines · 95 tokens per session scan A a95b1f686c47

Subscribe to this mod's changes

quantitative-analysis is a skill published in the GitHub repository cbrock84/headcount (1,247 stars, last pushed 3d ago), licensed MIT. It adds 95 tokens to every session and 961 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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