A Literature Review Matrix, Filled In for You
A literature review matrix puts one study in each row and one detail you want to compare in each column — study design, sample size, population, main findings. Filling one in by hand means reading every paper and copying the same facts into a spreadsheet, over and over.
Paper Digest Literature Matrix does that data extraction for you. Add up to 5 papers, choose your columns, and AI reads each paper and fills in its row — with a quote from the paper behind every value, so nothing has to be taken on trust. Looking for a written summary of the most important work on a topic instead? That is the AI literature review; for a full report on any question, use Deep Research.
Three Ways to Add Papers
Mix them freely: a table can hold papers from search, from your library, and from your own files at the same time.
Search Paper Digest
Click Search papers, search by title or topic, and pick up to 5 results. Each paper is read in full when its PDF can be downloaded; otherwise its title and abstract are used, and the row is marked Abstract only.
From My Library
Papers saved in your research library that have a PDF, and the files you added through the Reader, can be added straight from your library — no download and upload needed.
Upload your PDFs
Drop in PDF or TXT files, up to 5 per table. PDFs with selectable text work; scanned PDFs are not supported yet.
Every Value Backed by a Quote
AI data extraction is only useful if you can check it. The matrix shows you where every answer came from.
Click to see the source
Each value comes with a quote copied from the paper. Click any cell to open the passage, highlighted in the paper's text.
Not reported, not guessed
If a paper does not state something, the cell says Not reported instead of filling the gap with a plausible-sounding answer.
Flagged when unsure
If an answer's quote cannot be found in the paper, the cell is marked with a warning sign, so you know exactly which values to double-check.
How the AI Literature Review Matrix Works
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Add up to 5 papers at www.paperdigest.org/matrix — from a search, from your library, or by uploading PDFs.
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Choose the columns. Summary, study design, sample size, and main findings are there by default; add population, methods, limitations, or columns of your own.
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AI reads each paper and fills in its row, with each paper's own title and authors as the row label. A table of 5 papers is ready in seconds.
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Check and export: click any value to see its source passage, then download the table as CSV or copy it into Excel or Google Sheets.
Columns for Any Question
Start from ready-made columns, or ask your own questions — new columns are filled in for every paper already in the table.
Ready-made columns
The columns most literature reviews need: summary, study design, sample size, main findings, population / data, methods, and limitations.
Your own columns
Name a column and describe what you want in plain language — for example, Funding source: "list every funding source named in the paper", or Dataset: "which datasets were used". Up to 10 columns per table.
Clean numbers and categories
Sample size comes back as a plain number and study design as one of a fixed set of categories — RCT, observational study, systematic review, and so on — so rows compare cleanly.
In your language
Answers can be written in Arabic, Chinese (Simplified and Traditional), English, French, German, Indonesian, Japanese, Korean, Portuguese, Spanish, and Vietnamese. Quotes stay in the paper's own language so you can check them against the source.
From Matrix to Your Workflow
Data extraction for systematic reviews
Pilot your data extraction form: define the fields as columns, test them on a few included studies, and refine the wording before extracting at scale.
Export to your tools
Click Export to download a CSV file that includes each value's source quote, or copy the table and paste it into Excel or Google Sheets.
Find the papers first
Not sure which papers to compare? Start with an AI literature review or a Deep Research report, save the key papers to your library, and compare them here.
Frequently Asked Questions
What is a literature review matrix?
A table that puts one study in each row and one detail you want to compare in each column — for example study design, sample size, and main findings. It is a standard way to organize a literature review or the data extraction step of a systematic review.
How are the values filled in?
Large language models read each paper and answer every column for it. Each answer comes with a quote copied from the paper, and you can click any cell to see that passage highlighted in the source text.
How many papers and columns can a table have?
Up to 5 papers and up to 10 columns per table. Each paper is read up to its first 10,000 words, after the reference list is removed.
Where can the papers come from?
Three places: a search of Paper Digest's index, your My Library, or PDF and TXT files you upload. You can mix them in one table.
What if a paper's PDF is not available?
Papers found by search are read in full when their PDF can be downloaded. Otherwise the row is filled from the paper's title and abstract and marked Abstract only, so expect more cells to say Not reported.
What happens when a paper does not report something?
The cell says Not reported instead of guessing. If an answer's quote cannot be found in the paper, the cell is flagged with a warning sign so you know to check it.
Can I add my own columns?
Yes. Name the column and, optionally, add instructions in plain language — for example, Funding source: "list every funding source named in the paper". The new column is filled in for every paper already in the table.
Which files can I upload?
PDFs with selectable text and TXT files. Scanned PDFs are not supported yet.
Can I export the table?
Yes. Download it as a CSV file that also includes each value's source quote, or copy the table and paste it into Excel or Google Sheets.
What languages are supported?
Answers can be written in Arabic, Chinese (Simplified and Traditional), English, French, German, Indonesian, Japanese, Korean, Portuguese, Spanish, and Vietnamese. Quotes stay in the paper's own language so you can check them against the source.
Do I need an account?
You can try it on a few papers without signing in. Paid plans have no usage limits, and adding papers from My Library requires signing in.
More questions? Email team@paperdigest.org or see the full FAQ.