Why a nightclub? Well, it’s a better model than a home loan. I’m talking here about technical debt, the concept that describes how retarding complexity (cost) builds up in software development and other activities, and how to manage this cost. A home loan is misleading because product development cost doesn’t spiral out of control due to missed interest payments over time. Costs blow out due to previously deferred or unanticipated socialisation costs being realised with a given change.
So what are socialisation costs? They are the costs incurred when you introduce a new element to an existing group: a new person to a nightclub, or a new feature into a product. Note that we can consider socialisation at multiple levels of the product – UX design, information architecture, etc – not just source code.
Why is socialisation so costly? Because in general you have to socialise each new element with all existing elements, and so you can expect each new element you add to cost more than the last. If you keep adding elements, and even if each pair socialises very cheaply, eventually socialisation cost dominates marginal cost and total cost.
What is the implication of poor socialisation? In a nightclub, this may be a fight, and consequent loss of business. In software, this may be delayed releases or operational issues or poor user experience, and consequent lack of business. If you build airplanes, it could cost billions of dollars.
What does this mean for software delivery, or brand management, or product management, or organisational change, or hiring people, or nightclub management, or any activity where there is continued pressure to add new elements, but accelerating cost of socialisation?
Well, consider that production (of stuff) achieves efficiencies of scale by shifting variable cost to fixed for a certain volume. But software delivery is not production, it is design, and continuous re-design in response to change in our understanding of business outcomes.
Change can be scaled by shifting socialisation costs to variable; we take a variable cost hit with each new element to reduce the likelihood we will pay a high price to socialise future elements. Then we can change and change again in a sustainable manner. We can also segment elements to ensure pairwise cost is zero between segments (architecture). But, ideally, we continue to jettison elements that aren’t adding sufficient value – this is the surest way minimise marginal socialisation cost and preserve business agility. We can deliver a continuous MVP.
So what does this add to the technical debt discussion? All models are wrong; some are useful. Technical debt is definitely useful, and reaches some of the same management conclusions as above.
For me, the nightclub model is a better holistic model for product management, not just for coding. It is more dynamic and reflective of a messy reality. Further, with an economic model of marginal cost, we can assess whether the economics of marginal value stack up. Who do we want in out nightclub? How do we ensure the mix is good for business? Who needs to leave?
What do you think?
Postscript: The Economic Model
We write total cost (C) as the sum of fixed costs (f), constant variable cost per-unit (v) and a factor representing socialisation cost per pair (s):
\[ C = f + vN + sN^2\]
Then marginal cost (M) may be written as:
\[ M = v + 2sN \]
Note: This post was originally published August 2014, and rebooted April 2015