How long is a piece of string? How high is up?
There are so many variables that go into the creation of an
application ... It is true of all human endeavors. You can't give an
accurate estimate until a product specification is complete. Then you
would base your estimate on your expectation as to your ability to
complete the analysis, the design, the coding and the testing. That
has to be based on your recollection of how long it has taken you to
do those things for a similarly sized task before now. Another thing
is the level of sophistication that will go into bullet proofing your
application and making it ever so user friendly.
There are a couple of truths that go along with any project of this
kind.
1. It will always take longer to complete a project than you think
it could or should. At the end of a long overdue project you'll be
able to tell where the time and effort went but you couldn't see it
coming at the beginning. Make what seems to be a reasonable estimate
and then double or triple it.
2. Once you deliver your application, having accomplished
everything in the specification, the requests for changes will come
pouring in. So, to the extent possible, involve your user community.
Hold regular meetings with them and let them know you value their
contributions. It can be valuable to get prototypes of the
application out at regular intervals. Getting them out a few days
before you meet with your users is a good idea. When you do that
you'll have to continually remind your users that this is the
direction the project is going and you need them to take it for a spin
to see if it looks like you're going to meet their needs. You will
have difficulties with your boss who will look at the first prototype
and figure that the project is all done.
3. Make sure you have a fairly complete product specification and
functional specification before you start designing with Access. Keep
at it until you can't think of anything else the application has to
do. Publish it to your user community and your boss. Once you get
into the actual designing and coding in Access you'll find other
things but if you start without having those two documents in hand
your project will take even longer because you won't know where you're
going and you won't know when you're done. Most people who aren't in
a formal development system fail to recognize just how important the
specifications and design are to the success of a project. Until
recently, IBM was the biggest manufacturer of software in the world.
For software development projects large and small the rule of thumb
was that 2/3 of every resource expended in the development was
expended in the specification and design. The coding and testing only
consumed 1/3 of the resources!
I believe that Stan Leszynski referred in one of his books to some
rules of thumb that he used for each element of an Access project
(circa Access 2.0 or 97). He had a team of developers who were well
practiced with Access and who sere doing the same things repeatedly.
One other thing to bear in mind as you work on estimates: You have a
lot of other things going on. You tend to estimate work on how much
devoted effort it takes to do a given thing. You tell your boss "It
looks like 4 weeks of effort". He immediately blocks out one calendar
month on the calendar. Exactly half the time you'll probably need to
be able to devote 4 weeks of effort.
Once you have some experience developing applications in that
environment you'll be better able to estimate. Until then it's kind
of a crap shoot.
HTH
