How to use flags in a model

Can someone explain how to use flags in a model simply (I.e. to indicate lease start dates)? For example, I see 1s and 0s used pretty frequently. And also, what is the reason they are used / what would have been the alternative otherwise? I understand they’re a bit easier to follow / audit
 

I’m able to follow them when built in a model but am struggling conceptually about how to think about them when building them from scratch on my own. Is there anyway I should think about them at their core / broken down? Thanks! 

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The idea is to always keep your model simple to follow. This also helps minimizes potential mistakes you could make when creating it!

Flags are useful when a formula becomes too complex to follow. By breaking the formula into two parts using a flag, you can make it easier to understand. The alternative is either having a long, hard to follow formula or just hardcoding (I like to keep my models dynamic, but it really depends on the situation).

I'll use your example of a start date for some lease. You can build this type of flag the following way:

  1. Have a place on an assumptions tab (or wherever you want to put it) where you can input a start date
  2. Create a new row above your lease calculation that returns "1" if the date from the assumptions tab matches the date on this tab (otherwise, return "0")
  3. Multiply the lease formula by this flag. This will make it so the lease only starts when the flag returns a "1." To keep it from resetting, you can either use the sum of all previous flags here or adjust the flag calculation so that once a "1" appears, future flags will also be a "1" (There are other ways to do this, but this is just an example)
 

Got it this makes a ton of sense. So I should think of flags as not just to show timing but as an actual input / switch (i.e. for visibility to see where on a timeline a lease starts) that id multiply 

 

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