Map Which Sources Actually Back Which Claim — Free
Most writing problems are coverage problems: one claim carries six sources, another carries none, and the second one reads exactly as confidently as the first. A matrix of claims against sources makes that visible in one screen, which is why it is worth doing before the draft is finished rather than after.
The proof surface
Free path: the card computes locally in the browser with no key and no account. Where an AI step helps, any free chat assistant works — Google AI Studio's free tier and Groq's free tier were both no-card and rate-limited when this page was reviewed on 2026-09-13 (limits change; check before you rely on them).
Why the flat version breaks
A bibliography proves that sources exist, not that they are attached to anything. Marking coverage per claim is a different exercise, and it takes ten minutes — the same ten minutes that turns a reference list into an argument.
How to build the matrix in four passes
Copy the actual sentences rather than a description of them. A claim written as 'nitrate stuff' cannot be checked later, and the matrix is only useful if the rows are quotable.
Source key in the note line, numbers in the middle column. Five kinds of source is enough for any student draft — the point is coverage, not a perfect taxonomy.
A source counts for a row if you have read the part that supports that sentence. Citing a paper because its title matches is the exact failure the matrix is designed to catch.
Every row with nothing behind it is boxed. Find a source or cut the sentence — those remain the only two honest options, and the earlier you take one of them the cheaper it is.
SAMPLE DATA, NOT A VERIFIED CLAIM: Essay 2, second draft · five claims · five sources · one unsupported row · one single-source row. Replace these values with your own source before you rely on anything.
What breaks first
Listing sources in the note only
A key without numbers against the claims is a bibliography. The numbers are the entire mechanism; a row with a blank middle column is the finding.
Counting a source you have not read
Claiming coverage from a title, an abstract or a citation in another paper is how a marker finds the weak sentence. If you have not read it, the row stays unsupported.
Treating coverage as agreement
Two sources that disagree still support a sentence that says the evidence is mixed. The matrix counts sources, not consensus, and the note column is where disagreement gets written down.
What you pay otherwise
| The usual route | What it leaves out | Cost |
|---|---|---|
| A marker's fixed penalty | An unsupported central claim, found at marking time | a grade band |
| Rebuilding the argument late | Finding the gap two days before the deadline | an unscheduled two days |
| Padding with citations | Sources that look like coverage but are not attached to anything | credibility |
| This page + the free citation coverage matrix | Computed in your tab, result on screen before you type anything | $0 |
Try the free citation coverage matrix
Five claims are already mapped with the source key in the header and one row unsupported. Add a number to that row and the wash band clears.
Open the free citation coverage matrix →Keep the work if you will use it again
Every claim, the source key, the coverage count and the unsupported-row band, with no account.
Every claim, the source count and the unsupported-row check stay free. The one-time tier adds the printable matrix plus the saved drafts behind it.
Boundary: This maps your own claims against your own sources; it does not check whether a source is reliable, current or correctly cited. Follow your institution's referencing rules and read what you cite.