Is Guesstimate and Estimate same in Agile?

Guesstimate and Estimate are very common terminologies used in Project Management.

Often we hear questions like:

Can you share the estimate?

Can you share the guesstimate please?

Can we say whether these questions are the same? Definitely not.

Guesstimate:

As the name suggests it involves "Guess Work".

Guesstimate - With Uncertainties

Let's try to understand a scenario:

I need to travel from place A to B. I have no much idea about my destination B. I am not sure about my mode of transport, travel duration and many other things. I know very few details like name of the place, approximate distance between my current place to destination.

In this case if someone ask me, how much time you need to reach the place B?  Definitely i won't be able to say the accurate time required. But i can very well say the approximate time required through guess work.

So, in simple terms, guesstimate is the value that we share based on the available information with lot of questions and uncertainties.

Estimate:

Estimate is the value that we provide after knowing all details. 

Estimate - With Clarity

Let's try to understand a scenario:

I need to travel from my home to office. In this case, i am aware of all details like distance, mode of transport, travel duration. I don't have any uncertainties or questions to clear. In this case, i can precisely say it will take 30 minutes or the value which is very much close to accurate value.

So, in simple terms, estimate is arrived after clarifying all questions and collecting all required details.

Guesstimate to estimate. Is it possible?

Of course, its possible. Difference between Guesstimate and Estimate is the gap that we can fill with the help of clarifying questions and collecting more required details.

In project plan, generally we start with a Guesstimate as we may not have all data and not sure about all dependencies. Eventually with more brainstorming and requirements clarification, guesstimate will turn into an estimate.

So result of requirements clarification, dependency management, requirement workshop, Brainstorming sessions will turn our guesstimates into estimates.