較差 is read as かくさ (kakusa) and means range.
かくさ
kakusa
にちかくさ
diurnal range (of temperature)
ねんかくさ
annual range (of temperature)
かくゆういろん
theory of comparative advantage
こうりょう
comparison
ちんぎんかくさ
pay gap
ないがいかかくさ
price variance between domestic and overseas markets
いっぴょうのかくさ
disparity between values of votes in different constituencies
かかくさ
price margin
にっしんしさ
heliocentric parallax
ちしんしさ
geocentric parallax
ひょうさ
margin (e.g. in a vote)
ちんぎんのかくさ
wage differential