[Orgmode] Re: Time computation errors

[Bernt Hansen]

"Francesco Pizzolante"
<fpz-djc/address@hidden> writes:

> Bernt Hansen wrote:
>>
>> I'm not sure what the answer to this is.  I use the clocking features to
>> summarize time spent working on tasks in clock reports only and I've
>> never had the need to deal with negative values or summing clocked
>> values manually in a table.
>>
>> Maybe other users have experience with summing times in tables outside
>> of clock reports?
>
> On example could be to determine the difference between the
> estimated effort and the time really spent. You would
> necessarily end up with negative durations (supposing that some
> asks took less time than the estimated effort).
>
> Does it make sense?

I don't personally use the clocking information like that.  I just make
3 columns - one for the quoted time (estimated effort) I sent to the
customer, one for the estimated effort which may changed during work on
the project and one for clocked time side by side.

I also snapshot the estimate for the project before starting work with 
C-c C-x i.  This gives me a local subtree table that looks something
like this:

#+BEGIN: columnview :hlines 1 :id local
| Task                             | Quoted | Estimated | CLOCKSUM |
|----------------------------------+--------+-----------+----------|
| * PROJECT Some Project           |        |      0:40 |     1:40 |
| ** Details (not a todo item)     |        |           |          |
| *** More details                 |        |           |          |
| ** DONE Task to be done          |        |      0:10 |     0:27 |
| ** DONE Review project materials |        |      0:30 |     1:13 |
| *** DONE Review document         |        |           |     1:13 |

It's pretty obvious to me when they don't match.

The actual number of minutes they're off by isn't important to me since
the effort estimate is normally a rough guess anyway and clocking is
exact (to the minute).  Doing a difference on these two columns doesn't
really make sense to me.

When comparing clocked time to estimates I'm more interested in
  - this task was overestimated alot
  - this task was underestimated alot

-Bernt