上 details
Examples
in terms of N; as a matter of N — names the domain within which a statement, a reason or a restriction holds
経験上、そういう話はだいたいうまくいかないよ。
keikenjou, sou iu hanashi wa daitai umaku ikanai yo.
From experience, that sort of deal usually doesn't work out. casual
健康上の理由で、来月から勤務時間を短くします。
kenkoujou no riyuu de, raigetsu kara kinmujikan o mijikaku shimasu.
For health reasons, I'll be cutting my working hours from next month. neutral
契約上、弊社から一方的に価格を変更することはできかねます。
keiyakujou, heisha kara ippouteki ni kakaku o henkou suru koto wa dekikanemasu.
Under the contract, we are not in a position to change the price unilaterally. formal
Formation
N（法律・健康・経験など）＋上（法律上・立場上）attaches to noun phrase (schematic)
Notes
×健康上理由. 経験上 and 立場上
leak into ordinary speech; 契約上 and 法律上 stay
written. The locative band (地球上, ネット上) is a
different word.
Related patterns
Similar
において is a free に-phrase and attaches to any noun, places and events included (会議において決定された "was decided at the meeting"); 〜上 is a bound suffix — no の, no に — that takes only an abstract noun naming a system of judgment (法律上, 健康上, 経験上), so ?会議上 has no reading to offer while 会議において does.
〜上 fuses straight onto an abstract noun with no の and states the domain a fact holds in, implying nothing about reality (法律上問題ない "there is no legal problem"); の上では needs the の, takes a record or a calculation as its noun, and its は marks that record off against an unspoken "…but in fact" (計算の上では間に合う) — 法律上問題ない claims there is no problem, 法律の上では問題ない all but says there is one.
Lookalikes
One kanji with two readings — 〜上 fuses onto an abstract noun with no の and names the domain a judgment holds in (安全上の問題 "a safety issue"), while 〜の上で takes an action noun and means "after doing it" (確認の上でご連絡します) — の is the only visible cue, and reading じょう as うえ turns "a safety issue" into "on top of safety".