исходя из + Genitive

The expression исходя из functions as a logical connector. While it literally means 'issuing from,' it is almost always translated as 'based on' or 'given the...' in a logical context.

1. Grammatical Structure:
It always governs the Genitive case because of the preposition из. The word исходя is technically a present gerund, but in many contexts, it has evolved into a fixed prepositional phrase. A highly frequent lexical chunk to remember is исходя из этого (based on this / proceeding from this). To introduce a full clause, use the construction исходя из того, что... (based on the fact that...), noting that commas are usually required both before исходя (when used mid-sentence) and before что.

2. Usage and Register:

• Formal Contexts: It is the standard choice for legal documents, scientific papers, and business reports. A direct formal synonym is на основании + Genitive (on the basis of).
• Logical Deduction: It implies a process of evaluation. You look at the facts and 'proceed' to a decision.
• Lexical Collocations: In this construction, it is almost exclusively used with abstract nouns related to information, logic, or conditions (e.g., опыт, данные, расчёты, факты, стоимость, ситуация, убеждения). As a preposition, it is not used with physical objects. For physical movement out of a place, Russian uses выходить из (e.g., выходя из здания, never исходя из здания).
• Casual Alternatives: In everyday speech, Russians often prefer судя по (judging by) or simply по + Dative.

3. Grammar and Punctuation Nuances:
The phrase has a dual identity, and punctuation depends on whether there is a specific logical actor (active voice) or no specific actor (often passive or impersonal sentences).

• With an Actor: When there is a clear subject performing the action (e.g., "we decided," "he concluded"), исходя из often retains its gerund nature and is set off by commas. Example: Мы приняли решение, исходя из новых данных. (We made the decision, proceeding from the new data). However, even with an actor, the comma may be omitted if the phrase is closely tied to the predicate and forms the core of the sentence's meaning. As a practical rule of thumb, when Исходя из... starts a sentence, it is almost always followed by a comma in modern usage.
• Without an Actor (No Comma): When the sentence is passive or impersonal (e.g., "the price is calculated," "the decision was made"), there is no one to "proceed" from the data. Here, it functions as a pure derived preposition (meaning 'on the basis of') and is not set off by commas. Example: Цена рассчитывается исходя из затрат. (The price is calculated based on costs).
• The Drop Test: To check if it's acting purely as a preposition, try dropping the word исходя. If the sentence still makes grammatical sense (e.g., Цена рассчитывается из затрат), no comma is needed.

Furthermore, if исходя из is preceded by the conjunction а and cannot be removed without breaking the sentence, no comma is placed between them (e.g., не из корысти, а исходя из своих убеждений).