diff --git a/README.md b/README.md
index a5918a9..a88b0e4 100644
--- a/README.md
+++ b/README.md
@@ -55,6 +55,11 @@ let expected_score = system.expected_score(&alice, &bob, now);
 assert!(Score(0.84) < expected_score);
 ```
 
+Research
+--------
+
+See `resarch/` for utilities to evaluate rating systems on real-world data.
+
 License
 -------
 
diff --git a/research/README.md b/research/README.md
new file mode 100644
index 0000000..bcbea4e
--- /dev/null
+++ b/research/README.md
@@ -0,0 +1,85 @@
+liglicko2 research utilities
+============================
+
+Utilities to evaluate rating systems on real-world data.
+
+Encounters
+----------
+
+Condense PGNs from https://database.lichess.org to CSV files with relevant
+data.
+
+```sh
+zstdcat lichess_db_standard_rated_*.pgn.zst | cargo run --release --bin pgn_to_encounters > encounters.csv
+```
+
+See `sample-encounters.csv` for an example of the output.
+
+Alternatively download standard chess encounters from 2013-01 to 2024-09:
+
+```sh
+wget https://database.lichess.org/standard-encounters-until-2024-09.csv.zst # 287G
+```
+
+Replay
+------
+
+Replay previously prepared encounters.
+
+```sh
+cat encounters.csv | cargo run --release --bin replay_encounters -- --min-deviation 30,45 --first-advantage 0,11
+```
+
+See `cargo run --release -- --help` for more rating system parameters.
+All combinations will be simulated, so beware of combinatorial explosion.
+
+Output will look something like this:
+
+```
+min_deviation,max_deviation,default_volatility,tau,first_advantage,rating_periods_per_day,avg_deviance
+30,500,0.09,0.75,11,0,0.28697
+30,500,0.09,0.75,11,0.001,0.28696
+30,500,0.09,0.75,11,0.05,0.28664
+30,500,0.09,0.75,11,0.1,0.28653
+30,500,0.09,0.75,11,0.21436,0.28635
+30,350,0.09,0.75,11,0,0.28605
+30,350,0.09,0.75,11,0.001,0.28605
+45,500,0.09,0.75,11,0,0.28591
+45,500,0.09,0.75,11,0.001,0.28591
+45,500,0.09,0.75,11,0.21436,0.28587
+45,500,0.09,0.75,11,0.1,0.28585
+45,500,0.09,0.75,11,0.05,0.28585
+30,350,0.09,0.75,11,0.05,0.28581
+30,350,0.09,0.75,11,0.1,0.28569
+30,350,0.09,0.75,11,0.21436,0.28549
+45,350,0.09,0.75,11,0,0.28526
+45,350,0.09,0.75,11,0.001,0.28526
+45,350,0.09,0.75,11,0.05,0.28520
+45,350,0.09,0.75,11,0.1,0.28517
+45,350,0.09,0.75,11,0.21436,0.28516
+# ---
+# Sample Blitz rating of thibault: 1393.0 (rd: 45.000, vola: 0.08395)
+# Sample Blitz rating of german11: 1176.9 (rd: 45.000, vola: 0.08606)
+# Sample Bullet rating of revoof: 1385.7 (rd: 45.000, vola: 0.08776)
+# Sample Bullet rating of drnykterstein: 2686.5 (rd: 45.566, vola: 0.08249)
+# Sample Bullet rating of penguingim1: 2575.4 (rd: 45.000, vola: 0.07959)
+# Sample Blitz rating of lance5500: 1999.5 (rd: 45.330, vola: 0.07738)
+# Sample Blitz rating of somethingpretentious: 1659.1 (rd: 45.000, vola: 0.07559)
+# Sample Classical rating of igormezentsev: 1663.4 (rd: 205.781, vola: 0.09000)
+# ---
+# Estimated UltraBullet distribution: p1=812.7 p10=1044.0 p50=1334.1 p90=1616.9 p99=1989.0, avg=1338.6
+# Estimated Bullet distribution: p1=548.0 p10=803.2 p50=1141.5 p90=1607.1 p99=1980.3, avg=1173.7
+# Estimated Blitz distribution: p1=501.6 p10=759.9 p50=1179.4 p90=1630.3 p99=1974.8, avg=1187.8
+# Estimated Bullet distribution: p1=548.0 p10=803.2 p50=1141.5 p90=1607.1 p99=1980.3, avg=1173.7
+# Estimated Classical distribution: p1=779.0 p10=1059.3 p50=1347.8 p90=1714.3 p99=2001.4, avg=1377.6
+# Estimated Correspondence distribution: p1=1100.9 p10=1261.6 p50=1440.1 p90=1754.5 p99=2050.9, avg=1484.0
+# ---
+# Distinct players: 5381208
+# Processed encounters: 1409000000 (last at: 2020-07-31 17:42:58)
+# Total errors: 0
+# ---
+```
+
+The most important part is the `avg_deviance` column, which is indicates
+the predictive power of the rating system with the given parameters
+(lower is better).