wilsonScore

wilsonScore.js

// https://www.evanmiller.org/how-not-to-sort-by-average-rating.html

const wilsonScore = (up, down) => {
  if (!up) return 0

  const n = up + down
  const z = 1.64485 // 1.0 = 85%, 1.6 = 95%
  const phat = up / n
  return (phat + ((z * z) / (2 * n)) - (z * Math.sqrt(((phat * (1 - phat)) + (z * z / (4 * n))) / n))) / (1 + (z * z / n))
}

export default wilsonScore;