Debate Cards
& Evidence Search:
Find Any Card in Seconds.
PrepSync is a debate search engine with 5.5M+ cards spanning every active LD, PF, and Policy topic. Search by argument, author, or tag. Free to start.
What Are Debate Cards?
A debate card — also called “ev” or evidence — is a piece of academic evidence cut from a source: an article, book, study, or report. Every argument you make needs one.
Every card has three parts: a tag (the one-line claim), a citation (author, year, publication), and the card text — the highlighted sentences read aloud in a round.
In competitive debate, the quality, recency, and source of your cards affects your win rate. Judges evaluate whether your evidence actually supports your tag.
Finding and cutting cards used to take hours of manual research. PrepSync lets you search 5.5M+ pre-cut cards instantly.
New to debate? How to debate: a complete beginner's guide →
How PrepSync Debate Evidence Search Works
Semantic Search
Type your argument in plain English. No Boolean operators, no exact-match frustration. AI finds cards that match your meaning, not just your words.
6-Way Query Rewriting
PrepSync rewrites your query into 6 semantic variants and searches all simultaneously, then fuses results using RRF ranking for the highest-relevance output.
Recency Weighting
Recent cards surface before outdated ones. Evidence from the last 2 years ranks higher by default — because judges care about whether your evidence is current.
Built by a Debater Who Needed It
I debated in high school and college at a program that didn't cut much prep. When I searched Logos for cards, the results had little connection to what I was looking for. Conceptual queries, philosophical arguments, anything that wasn't an exact keyword match: Logos couldn't return them.
The teams I lost to in college read evidence I had never seen. They ran arguments that hit on-point from credible sources. I searched the same topics and came up empty. By my senior year at Florida State running NFA LD, that gap was the difference between a clean prelim record and going 3-3 at nationals three years straight. The problem wasn't research time. It was the search engine.
My program had no institutional prep budget. I couldn't close that gap with a keyword search engine. So I built PrepSync. Once finding cards took minutes instead of hours, I stopped prepping the 1NC and started prepping the 1NR: extensions, drills, narrative overviews, blocks. That's where rounds get decided.
Logos returns keyword matches. Debate arguments don't work that way. “Populism kills people” is not a phrase anyone writes in a law journal. The evidence exists. A keyword engine can't find it.
PrepSync rewrites your query six ways, searches all variants simultaneously, and fuses results by relevance rank. You type the argument. The engine handles the rest.
The free tier at Logos returned too little to be useful. PrepSync's full search is free. Losing rounds to a paywalled search engine is not a skill gap.
PrepSync vs. Logos Debate: 33-Query Benchmark
We ran 33 real debate search queries across both platforms, scoring each result 1–9 based on relevance (higher = stronger, more on-topic card). Scores were tallied across the top 20 results per query. Study conducted by the PrepSync team, June 2026.
| # | Query | PrepSync | Logos | Winner |
|---|---|---|---|---|
| 1 | populism kills people | 124 | 58 | +114% |
| 2 | the global economy relies on the U.S. economy | 159 | 93 | +71% |
| 3 | authoritarian leaders exacerbate terrorism | 117 | 64 | +83% |
| 4 | international law is really good | 141 | 86 | +64% |
| 5 | africa foreign investors care about potential | 107 | 63 | +70% |
| 6 | AI bubble pops soon | 148 | 107 | +38% |
| 7 | time travel is wrong | 91 | 51 | +78% |
| 8 | baudrillard homophobic | 104 | 70 | +49% |
| 9 | recession exacerbates poverty | 158 | 126 | +25% |
| 10 | U.S. cyber defense is strong now | 143 | 112 | +28% |
| 11 | populism precedes authoritarianism | 102 | 74 | +38% |
| 12 | universal healthcare doesn't solve pandemics | 132 | 109 | +21% |
| 13 | economic development outweighs environmental protection | 121 | 101 | +20% |
| 14 | no pandemics | 144 | 126 | +14% |
| 15 | cognitive biases are fake | 91 | 75 | +21% |
| 16 | desalination is good for fishing and the environment | 84 | 69 | +22% |
| 17 | antibiotic resistant diseases affect minorities | 82 | 67 | +22% |
| 18 | credit not necessary for loans | 74 | 62 | +19% |
| 19 | climate change causes extinction | 177 | 165 | +7% |
| 20 | categorical imperative | 149 | 137 | +9% |
| Feature | PrepSync | Logos Debate |
|---|---|---|
| Evidence library | 5.5M+ cards | ~1M cards |
| Search type | AI semantic search | Keyword only |
| Free tier | Yes — full search free | No |
| Judge paradigms | Yes — 10,000+ judges | No |
| Competitor records | Yes | No |
| AI card cutting | Yes | No |
| Active development | Yes | No longer maintained |
Logos Debate is no longer actively maintained. PrepSync is built for the current season.
Find Debate Evidence for Your Format
Debate Cards — Frequently Asked Questions
What are debate cards?
Cards are pieces of cited evidence cut from academic sources — articles, books, studies, or reports. Each has a tag (the claim), a citation (author, year, source), and card text read aloud in rounds. Debaters use cards to support their arguments with external evidence.
What is debate ev?
“Ev” is short for evidence. When debaters say “run ev” or “read ev” they mean reading a card in a round. High-quality ev from credible, recent sources wins rounds. Judges evaluate whether your evidence actually supports your tag.
What is debate evidence?
Debate evidence (also called a card or ev) is a piece of text cut from an academic source — an article, book, study, or report — used to support a claim in a round. Each piece has three parts: a tag (the one-line claim), a citation (author, year, source), and the highlighted card text read aloud. Good evidence has a credible source, a clear warrant, and a tag that accurately reflects the argument.
What is a debate search engine?
A debate search engine indexes pre-cut debate cards so debaters can search by argument, topic, or author instead of manually researching and cutting from scratch. PrepSync is the largest free debate search engine with 5.5M+ cards and AI-powered semantic search.
What is Logos Debate?
Logos Debate was a debate evidence search engine used by high school and college debaters to find pre-cut cards for LD, PF, and Policy rounds. It is no longer actively maintained. PrepSync is the actively developed alternative — AI-powered semantic search, 5.5M+ cards, judge paradigms, and competitor records, free to start.
Is Logos Debate still active?
Logos Debate is no longer actively maintained. PrepSync is the actively developed alternative with AI-powered search, 5.5M+ cards, judge paradigms, and competitor records — free to start.
What is debate logos?
In debate, “logos” (from Greek) refers to logical or evidence-based appeals — using facts, data, and reasoning to persuade. Logos Debate was a search engine named after this concept. The platform is no longer maintained.
How do I find evidence for the current LD topic?
Search on PrepSync with your argument in plain English. AI rewrites your query and returns the most relevant, recent cards for the current Lincoln-Douglas resolution. No Boolean operators needed.
How do I find evidence for the current PF topic?
Search by your contention or impact claim on PrepSync. The engine surfaces the best matching cards from its 5.5M+ library for the current Public Forum resolution. Results rank by relevance and recency.
What is a debate tag?
A tag is the one-line claim at the top of every card. It summarizes the card's argument in a bold, impact-first sentence. A good tag tells the judge exactly what the card proves before a word of evidence is read.
The Debate Search Engine
Built for This Season.
5.5M+ cards. AI-powered. Judge paradigms. Free to start.