偏差値

• 読み: へんさち
• ローマ字: hensachi
• 漢字の分解: 偏 (hen) — deviate, lean; 差 (sa) — difference; 値 (chi) — value
• 発音: /heɴ.sa.tɕi/

意味

Deviation value; standardised test score. A standardised score used in Japan's education system indicating how far a student's performance deviates from the mean.

Japan's education system uses 偏差値 (a form of T-score, mean 50, standard deviation 10) extensively to rank students and universities. A 偏差値 of 70 places a student roughly in the top 2% of test-takers. University rankings in Japan are almost universally expressed in terms of 偏差値, making it a central concept in entrance exam culture (受験文化). The term is culturally loaded — high school students obsess over it, and critics argue it reduces education to a single number.

例文

1. 志望する大学の偏差値が自分の実力より10ポイント以上高く、予備校では難関校として分類されていた。
2. 偏差値だけで大学を選ぶのではなく、学びたい学問や将来のキャリアを考慮すべきだという意見が増えている。
3. 彼女は三年間の浪人生活を経て、念願の偏差値70超の国立大学に合格した。

使い方ガイド

場面: education, university entrance exams, school rankings, student life

トーン: neutral, culturally significant

起源と歴史

Compound of 偏差 (hensa — deviation, divergence from the mean; from 偏 to lean/deviate + 差 difference) and 値 (chi/atai — value, numerical value). Introduced to Japan's educational testing system in the post-war period as a statistical measure to normalise test scores across different examinations.

文化的背景

時代: Showa-Modern

世代: Youth to Adult

社会的背景: Universal