The Toilet Paper Replenishment Process

Don Norman has an excellent blog posting about the poor design of many Toilet Paper Dispensers - focusing mainly on the poor algorithms that we simple humans use when given a choice of which roll to use from a multi-roll dispenser... Multi-roll TP dispensers prove Don's thesis that many every day things just aren't designed well. I had read Don's book and seen his blog long ago, but it came back to mind when I encountered the following in a bathroom in Stanford University's Terman Engineering Building...

No less than six partial rolls of toilet paper perched on top of a standard two roll toilet paper dispenser.

Obviously Don is right about the design of the dispenser itself... Given the choice of which roll to use we'll pull sheets off each. But obviously there's something more at work here: The process for refilling the dispenser is suspect.

I suspect the process is something like the following:

Check the dispenser each day. If either of the rolls is less than 1/4 full
replace it with a full roll and place the partial roll on top of the dispenser.

The objective of this process is to make sure that there's always plenty of toilet paper available... Obviously you don't want to run out.

My guess is that the partial roll is left on the dispenser in the hopes that folks will use it - This is much better than throwing it away, and given frugal college students I'm surprised that the partials aren't disappearing.

The flaw in the process seems pretty simple... "Enough Toilet Paper on Hand" doesn't take into account the partial rolls. Instead of basing replacement on the size of the rolls installed in the dispenser, it really ought to be based on the total amount of tissue on hand - the rolls in the dispensers plus the partials.

At first glance this appears to be a classic example of mis-stating the objective of the process. The janitor who refills the dispenser has been told something like "No roll on the dispenser should be less than 1/4 full". The real objective should probably be something like "There should always be the equivalent of a full roll on hand".

Having restated the objective: What if you ended up an "equivalent full roll" made up of sixteen partial rolls? That certainly wouldn't be acceptable to most folks.



Returning to Don Norman's point - the design of the dispenser itself is really at the heart of this "process" problem. The process for refilling the dispenser is overly complex due to the poor design of the dispenser itself. Try as we might to give proper instructions to the janitor, success is going to be highly dependent on the janitor's judgement on whether or not enough toilet paper is on hand.

What can we learn from this example?

If a process that should be simple isn't, then look beyond the process definition: It may be better to buy a new dispenser than to figure out how to refill the one that you have.

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UPDATE:

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Prompted by the comment of a good friend and Stanford Alum I delved a bit deeper into the conundrum and sadly discovered that this is both a Process and a Design problem... In another bathroom at Stanford I discovered the following shocking sight:

The superior design of this multi-roll dispenser has been thwarted by the installation of two such dispensers... The point of the design was to eliminate choice (thus simplifying the refill process) - introducing a second dispenser nixes that advantage... and as you can see the "refill process" is still needlessly removing partial rolls.

Such a thing would never have happened at my alma matter (Rice University) ;-)