Re: Re: SIP is "just another Six Sigma measure"?

On 2003.01.21, Tom Poppendieck <[email protected]> wrote:
> There is a very short tutorial on these manufacturing
> operations terms at
> http://hbswk.hbs.edu/pubcontent/toolkit/operations/index.html
> If you know how to do laundry, this introduction will be
> useful.

Thanks, Tom!  This is excellent.

On 2003.01.21, Kent Beck <[email protected]> wrote:
> 
> Suzuki "The New Manufacturing Challenge", p 131.
>   * Cycle time: Time between the completion of the last
> product and the completion of the next product
>   * Production lead time: Time between beginning of
> production and completion of production for a single product

Looking at the definitions presented by the Operations Basics Workbook
that Tom pointed us to, it seems that:

Cycle time: "Cycle Time is the length of time, on average, that it takes
to complete a step or set of steps within an operation."

Manufacturing Lead Time (MLT): "Manufacturing lead-time, or MLT, is the
average length of time it will take a new set of inputs to move all the
way through the operation, assuming no unusual measures are taken.
[...] Little's Law states that:
    Manufacturing Lead Time = Cycle Time * Work-in-Process"

Given this, Software-In-Process is the sum of Cycle Time of all the
steps required, since MLT accounts for Work-in-Process.
Software-Lead-Time (the analogue to MLT) would be "SIP * Number of
Features" ... right?

Or, are you really looking to make SIP identical to MLT?  In other
words, if we have 10 features to implement, and on average our
Conception phase takes 3 days (conception cycle time = 3 days), our
design/test/code phase takes 2 weeks (coding cycle time = 10 days) and
our customer review phase takes 1 day (review cycle time = 1 day),
therefore our whole process cycle time is 14 days ... times 10 features
yields a MLT of 140 days -- we'd have a SIP of 140 days?

-- Dossy

-- 
Dossy Shiobara                       mail: [email protected] 
Panoptic Computer Network             web: http://www.panoptic.com/ 
  "He realized the fastest way to change is to laugh at your own
    folly -- then you can let go and quickly move on." (p. 70)

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