GBAL - 'can't transfer between two boots / trunks' conundrum

GBAL is a very powerful feature, however, this power comes with its challenges.

One such challenge we call 'can't transfer between two boots (trunks)' issue.

Imagine two identical cars, side by side.  

One car is full of stuff, the other not.

(the analogy being that the full car on the left represents GBAL bookings in virtual space, the empty one on the right represents physical bikes when they are allocated)

GBAL allows you to 'fill-up the boot / trunk' whilst not overfilling it.

But then when you allocate you transfer from the left to the right.

Of course, if you can fill the left-hand side, if the car is identical, then you can theoretically fill the right-hand boot.

Same stuff.  Same space.

The problem comes when reality doesn't meet theory.

For example, if I choose to move over the little stuff first, then the big stuff (skis / bike etc) there won't be room.

So, in other words, poor allocation choices can lead to being unable to fulfil orders that you were theoretically capable of fulfilling (with ideal allocation).

Then of course there are self-inflicted problems.

I have a full car of stuff.  (Full bookings for some Product Lines).

But then I sell some bikes (or some bikes get broken)

Now, my car just got smaller - so there cannot be enough space (if I'm operating at or near capacity)

How about a concrete example in BRM I can really get my head around?

Take this example.

I have a product line (let's say a Specialized Stumpjumper 27.5 size M)

I have 4 of them.

I fill up all 4 bikes, using GBAL over 4 days, with a total of 7 bookings.

• 3 x 4-day bookings
• 4 x 1-day bookings

In the good scenario (top right) I make sensible allocation choices and I can fulfil even at 100% capacity.

in the bad scenario (bottom right) I make poor allocation choices and I can't fulfil.

Moral of the story...

1. we are going to re-write the GBAL algorithm to provide the same functionality without this issue, and more clarity.
2. don't operate at capacity - you will have no room for manoeuvre:
   1. you need to make perfect allocation choices
      
   2. you can't reduce your capacity: break anything (or have it stolen, returned late etc)
3. You can use the holdback % feature to not get up to capacity on your Product Lines

See Also

what is GBAL actually doing - behind the scenes?