Bob
I'm not sure if there is a real difference. Whether it is a PO or a
dependent demand, one is satisfying a need with a service or a good. No
matter what you call it it is a request for item, quantity and price
(information) coupled with a linked payment stream. A distinction can be
drawn between push and pull mechanism but ultimately it is the user with
the need who initiates the process.
Andrew Macpherson
----------
> From: Bob Haugen <[email protected]>
> To: [email protected]; [email protected]
> Subject: POs considered harmful for dependent demands
> Date: Tuesday, 15 February 2000 3:51
>
> Maybe everybody already knows this, so this is the short version.
> I have included this point in a different message, but wanted to
> make sure it was as clear as I could make it.
>
> I still see documents going to this list that seem to assume
> that purchase orders are the way all B2B ecommerce is done.
>
> PO's are not a good mechanism for dependent demands,
> and if they are set in stone in ebXML in such a way that
> it is difficult to do business without using them, it will
> need to be redone for Internet-mediated commerce.
>
> Dependent demands are demands that are dependent on some
> other demand, usually called the independent demand.
> This concept comes from MRP, the predecessor (and still
> included in) ERP software.
>
> Dependent demands include the components of manufactured
> products, retail replenishments, shipping for almost any
> purchased item, etc.
>
> Purchase orders are a carryover from paper systems.
> They are usually composed of a collection of line items,
> often aggregating quantities over time periods. They
> have no knowledge of how the purchases items
> will be used, nor what processes and components
> are required to fulfill the order.
>
> Dependent demands, by contrast, are totally dependent
> on whatever independent demand stimulated them in the
> first place.
>
> All dependent demands should be linked to their
> relative independent demand so if there are changes
> anywhere in the network of activities, they can be
> rippled out to the affected relatives.
>
> For example, if a customer order for a finished good
> changes in quantity or timing or is cancelled - the
> dependent demands should be changed correspondingly.
>
> The PO is too heavy a mechanism for managing
> dependent demands - something more like an
> electronic Kanban or manufacturing schedule
> or point-of-sale event notification would be
> better.
>
> The same goes for invoices, which are unnecessary
> for dependent demands.
>
> Comments? Violent disagreement or agreement?
>
> -Bob Haugen
>
