[kplato] definitions of effort and risk

[Jim Sabatke]

Normally, the effort column would be modified to include risk.

By entering values in the Pessimistic, Expected and Optimistic columns; 
and by including a column for risk level (confidence level) the effort 
value would be calculated.  In the project management discipline, the 
effort value is normally calculated as follows (with a 99% confidence 
level):

                Effort                           + 4 Effort            
      + Effort
                        pessimistic                       Expected    
            Optimistic
          -------------------------------------------------
                                                                 6


There are other calculations if the risk is greater, which it normally 
is for software

                E(p) + 4 E(e) + 2 E(o)                                
E(p) + 4 E(e) + E(o)
                ----------------            or even       ---------------
                                7                                        
                          3.2

The last formula generally gives a 95% confidence level.  It is possible 
easily calculate std. dev. from the formulas and do a Z score lookup to 
get an exact confidence level; but the formulas listed are considered 
adequate for project work.

Accordingly, the expected effort field should have the first entry.  The 
effort field will be the expected effort value unless the other (p) and 
(o) efforts and confidence level have values entered; then the effort 
value will be computed.

Does this make more sense?

Jim
bilbo wrote:

>On 21 Jun 2001, at 17:23, Jim Sabatke wrote:
>
>>For the purposes of this project:
>>
>>Effort is the amount of actual time (hours, weeks, minutes...) that a 
>>given task requires for completion.
>>
>>Risk, I'll have to think about that one as there are so many kinds of 
>>risk in a project.  You CAN look at it as a quantifiable variance on effort.
>>
>
>What are we going to call the estimate for the time required to 
>complete a task?
>
>Do we need two (or more) attributes here?
>Perhaps 'uncertainty' and 'risk'. 
>Uncertainty being your quantifiable variance - a plus/minus value 
>applicable to the estimated work - because there should be no 
>uncertainty on an actual. The uncertainty could be expressed as 
>either a value (of the same units as the estimate), or as a 
>percentage.
>Risk could be considered as a confidence level (percentage) that 
>the estimate is correct. I.e. if you're estimating a software project 
>you could have a risk of 50%, but for a manufacturing project with 
>an established production line then risk could be 99%. I think I'm 
>meaning confidence rather than risk.
>
>Am I way off base here? If so I'll shut up.
>
>regards,
>        Bill
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-- 
Jim Sabatke
SuSE 7.1 Linux
Kernel - 2.4.0
http://www.execpc.com/~jsabatke

"People tell me that I'm fading fast, that I can't last the whole night through" Janis Ian