Going through a document for proof reading, I came across the phrase "In this stage, the model is put into operation" and was kind of confused. Mostly I had heard "At this stage ...", i.e. "at" instead of "in". I had a quick look over the net, and could find "In this stage ..." has been also used, however, I am doubtful about:

  • This particular usage
  • What is the proper use cases of these two phrases
  • @Chappo This should be posted as answer. Thank you for such a nice explanation. Dec 12, 2018 at 7:10

2 Answers 2


The choice of preposition here is a subtle one. It's useful to look at the relevant definitions:

at (1)

  1. Expressing the time when an event takes place.
    • ‘the children go to bed at nine o'clock’
    • ‘his death came at a time when the movement was split’

[Oxford Dictionaries]

In this particular context, "at" identifies a specific moment in the process/timeline. Compare this with:

in (1)

  1. Expressing a period of time during which an event happens or a situation remains the case.
    • ‘at one o'clock in the morning’
    • ‘Nobody who is associated with the bank in that period can come out with any credit.’

[Oxford Dictionaries]

Thus, "in" is more general and, in the context of your sentence, covers anything that happened during that stage.

To some degree the choice of preposition is also influenced by the broader context. If the discussion is about the stage itself, then the action happens in (during) that stage. If the discussion is focused on the model itself, then you would describe at what point it's put into operation.


At this stage: While used in a conversation, specifying to the on-going window of time.

In this stage: While used in a conversation, specifying to a physical platform.

Depending on the context, use of the right preposition. If the explanation is about the model in specific, then use "in this stage'. If the explanation is about a certain process or system, use "at this stage".

EDIT: Blunder, Blunder...Shower and Thunder! |Typing error|

  • Thanks for the reply, but I guess there is a typo, since "in this stage" has come twice Dec 12, 2018 at 6:17

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