Generally speaking, estimation is
very important aspect in project life cycle. It’s not important while project
planning only, but as a project manager estimation is the process which is
performed throughout the project life cycle. New changes or scope creep can revise
estimation which was performed earlier, so it’s continuous operation required.
Estimation can be done by Project
resources who allocated for it or at the initial level when resources are not
decided then any subject matter Expert (SME) can perform the estimation. SME
can discuss with Quality Assurance team for it or if necessary brainstorming of
other experts to get proper estimation.
Sometimes estimation cannot be
done instead of that guesstimation is done due to lack of time, management or
process. Estimation require proper time to be in detail but sometimes time is
not available to estimate so with the help of any past experience or some
detail estimation can be done, that’s called guesstimation. If your luck is
fine or God is with you then guesstimation can be accurate otherwise it will
lead towards wrong estimated time and project cannot be delivered on time.
In mature organisation, project
manager will get standard or template for estimation which organisation
follows, same time organisation can provide estimation techniques which they
follow or prefer, on the contrary some organisation just follow guesstimation
for project and where project run with the risk.
To sum up, proper estimation can
give you the accurate vision about time, cost and scope with risk management too,
while guesstimation can create extra risks for the project and it will lead
project towards the failure.