From 9247d1fb5b5f00214899b115b3a021b4498de5c3 Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Sat, 20 May 2023 23:10:34 +0200
Subject: [PATCH] Add per-point CIs.

---
 ultimate.js | 60 +++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 47 insertions(+), 13 deletions(-)

diff --git a/ultimate.js b/ultimate.js
index 54348cd..7c265c2 100644
--- a/ultimate.js
+++ b/ultimate.js
@@ -74,7 +74,11 @@ function add_3cell_ci(tr, ci) {
 	const width = 100;
 	const height = 20;
 	let svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
-	svg.classList.add('ci');
+	if (ci.inverted === true) {
+		svg.classList.add('invertedci');
+	} else {
+		svg.classList.add('ci');
+	}
 	svg.setAttribute('width', width);
 	svg.setAttribute('height', height);
 
@@ -513,6 +517,32 @@ function make_efficiency_ci(points_won, points_completed, z)
 	return ci;
 }
 
+// Ds, throwaways and drops can happen multiple times per point,
+// so they are Poisson distributed.
+//
+// Modified Wald (recommended by http://www.ine.pt/revstat/pdf/rs120203.pdf
+// since our rates are definitely below 2 per point).
+function make_poisson_ci(val, num, z, inverted)
+{
+	let low  = (val == 0) ? 0.0 : ((val - 0.5) - Math.sqrt(val - 0.5)) / num;
+	let high = (val == 0) ? -Math.log(0.025) / num : ((val + 0.5) + Math.sqrt(val + 0.5)) / num;
+
+	// Fix the signs so that we don't get -0.00.
+	low = Math.max(low, 0.0);
+
+	// The display range of 0 to 0.25 is fairly arbitrary. So is the desired 0.05 per point.
+	let avg = val / num;
+	return {
+		'val': avg,
+		'lower_ci': low,
+		'upper_ci': high,
+		'min': 0.0,
+		'max': 0.25,
+		'desired': 0.05,
+		'inverted': inverted,
+	};
+}
+
 function make_table_general(players) {
 	let rows = [];
 	{
@@ -744,24 +774,28 @@ function make_table_per_point(players) {
 	let touches = 0;
 	for (const [q,p] of Object.entries(players)) {
 		if (q === 'globals') continue;
+
+		// Can only happen once per point, so these are binomials.
+		let ci_goals = make_binomial_ci(p.goals, p.points_played, z);
+		let ci_assists = make_binomial_ci(p.assists, p.points_played, z);
+		let ci_hockey_assists = make_binomial_ci(p.hockey_assists, p.points_played, z);
+		// Arbitrarily desire at least 10% (not everybody can score or assist).
+		ci_goals.desired = 0.1;
+		ci_assists.desired = 0.1;
+		ci_hockey_assists.desired = 0.1;
+
 		let row = document.createElement('tr');
 		add_3cell(row, p.name, 'name');  // TODO: number?
+		add_3cell_ci(row, ci_goals);
+		add_3cell_ci(row, ci_assists);
+		add_3cell_ci(row, ci_hockey_assists);
+		add_3cell_ci(row, make_poisson_ci(p.defenses, p.points_played, z));
+		add_3cell_ci(row, make_poisson_ci(p.throwaways, p.points_played, z, true));
+		add_3cell_ci(row, make_poisson_ci(p.drops, p.points_played, z, true));
 		if (p.points_played > 0) {
-			add_3cell(row, p.goals == 0 ? 0 : (p.goals / p.points_played).toFixed(2));
-			add_3cell(row, p.assists == 0 ? 0 : (p.assists / p.points_played).toFixed(2));
-			add_3cell(row, p.hockey_assists == 0 ? 0 : (p.hockey_assists / p.points_played).toFixed(2));
-			add_3cell(row, p.defenses == 0 ? 0 : (p.defenses / p.points_played).toFixed(2));
-			add_3cell(row, p.throwaways == 0 ? 0 : (p.throwaways / p.points_played).toFixed(2));
-			add_3cell(row, p.drops == 0 ? 0 : (p.drops / p.points_played).toFixed(2));
 			add_3cell(row, p.touches == 0 ? 0 : (p.touches / p.points_played).toFixed(2));
 		} else {
 			add_3cell(row, 'N/A');
-			add_3cell(row, 'N/A');
-			add_3cell(row, 'N/A');
-			add_3cell(row, 'N/A');
-			add_3cell(row, 'N/A');
-			add_3cell(row, 'N/A');
-			add_3cell(row, 'N/A');
 		}
 		rows.push(row);
 
-- 
2.39.2