Translation guide
The English word 'incidence' refers to the rate or frequency at which something (usually negative) occurs. In Japanese, this concept is expressed differently depending on context, such as disease rates, crime statistics, or general occurrence. There is no single direct equivalent; instead, use words for 'rate', 'frequency', or 'occurrence' as appropriate.
To express how often something happens, particularly in medical, statistical, or formal contexts.
Literally 'occurrence rate'. Commonly used for disease incidence, accident rates, etc. Neutral and widely understood.
この地域のガンの発生率は高い。
The incidence of cancer in this region is high.
Specifically 'morbidity rate' or 'incidence rate' in epidemiology. More technical than 発生率.
インフルエンザの罹患率が上昇している。
The incidence of influenza is rising.
Means 'frequency'. Can be used for incidence in a general sense, but less specific to rates.
交通事故の頻度が減った。
The incidence of traffic accidents has decreased.
Specifically 'onset rate' for diseases. Used in medical contexts.
この病気の発症率は低い。
The incidence of this disease is low.
To talk about the fact that something happens, without focusing on the rate.
Means 'occurrence' or 'outbreak'. Used for events, problems, etc. Often used in news reports.
犯罪の発生が増えている。
The incidence of crime is increasing.
Nominalized form of 'to happen'. More colloquial and general.
こういう問題が起こることは珍しくない。
The incidence of such problems is not rare.
To express the extent to which something affects a group, often in economics or policy.
Means 'burden'. Used in phrases like 'tax incidence' (税の負担).
消費税の負担は低所得者に重くのしかかる。
The incidence of consumption tax falls heavily on low-income earners.
Literally 'the range over which influence extends'. A more explanatory phrase for incidence in policy contexts.
この政策の影響の及ぶ範囲を分析する必要がある。
We need to analyze the incidence of this policy.
There is no single Japanese word that covers all uses of 'incidence'. Using a dictionary lookup like 入射 (incidence of light) or インシデンス (loanword) is usually wrong outside specific technical fields. Always consider the context: rate, occurrence, or burden.
光の入射角
angle of incidence (of light)