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Growth marketing & the theory of constraints

Article originally published in September 2023 by Stuart Brameld. Most recent update in April 2024.

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In marketing and growth, one of the most critical factors to team performance is speed (or more specifically velocity). As growth marketers the more efficient our systems, the more experiments we can run, and the more experiments we run, the faster we learn.

Twitter grew rapidly between 2010 and 2012, and it’s then VP of Product (Satya Patel) attributes this rapid growth to a significant increase in experimentation and testing velocity.

Ramp is currently the fastest-growing SaaS startup of all time and in a recent interview with Lenny Rachitsky Ramp’s VP of Product said the following:

“Velocity is everything at Ramp. It’s how we design our product development process. It’s how we incentivise teams. It’s who we want to hire. It’s who we want to promote. It’s everything around how we make decisions and how we organise the organisation.”

Geoff Charles, VP Product

If speed and velocity are a key factor for growth, our job as growth leaders is to remove the constraints that slow us down.

What is a constraint?

constraint (noun) is defined as:

“something that controls what you do by keeping you within particular limits”

Cambridge Dictionary

In manufacturing, a constraint is often referred to as a bottleneck.

From a growth marketing perspective, a constraint is anything that limits our performance.

What is the theory of constraints?

The Goal by Eliyahu Goldratt first popularised the theory of constraints, and it remains one of the most widely read business books of all time.

First published in 2004 it tells the story of a struggling manufacturing plant manager who has just 90 days to save his underperforming plant from being shutdown. Naturally, the theory of constraints saves the plant and its hundreds of employees from losing their jobs.

The theory of constraints states that there is, and will always be, a constraining or limiting factor in any process or system and that output is always determined by this one constraint.

Translating the theory to growth and experimentation we can say that:

  1. Every experiment will have one and always one constraint
  2. The slowest part of your experiment constrains the entire experiment (no experiment can move faster than its slowest part)
  3. Once you’ve identified the constraint in your experiment, focusing on any other activity that doesn’t fix it is irrational

Identifying the constraint

If it’s not immediately obvious where the constraint may be, here are some questions to ask. You should be asking these questions before running growth experiments.

  • Where could things get stuck?
  • Where are the biggest risks?
  • Which step in the process is likely to take the longest time?
  • Which elements of the process are outside of my control?

Option 1: Reducing scope

Growth marketers tend to run fixed time rather than fixed scope experiments so consider how you can reduce the scope to fit the time available.

Apply the Pareto Principle (often known as the 80/20 Rule) to your experiment. The 80/20 rules describes how, in most systems, 80% of the outputs come from only 20% of the inputs. In other words, 80% of your results come from only 20% of your efforts.

  • Can you reduce the scope of your experiment whilst still delivering the core outcome that is needed to test your hypothesis?
  • What is really important versus a nice-to-have?

Option 2: Reducing interdependencies

Where are the interdependencies in your experiment, and can you reduce (or eliminate) reliance on other teams – particularly before the idea has been validated and proven. This is particularly relevant in large companies as traditionally the focus of management has been in optimising individual functions, rather than flow through the entire organisation.

Questions to ask yourself:

  • Are you dependent on another team for approvals, resources, people, information, equipment or policies?
  • If so, how can you reduce these interdependencies? Are they really required?

For example:

  1. Approval – Is approval really required at this stage?
  2. People – Can we ship an initial version using expertise that exists within our team?
  3. Expertise – Can we avoid the need to involve 3rd party agencies or contractors?

“An organisation can only be as agile as its least agile division”

Evan Leybourn, Evan’s Theory of Agile Constraints

In general, reducing reliance on other teams for experimentation means less waiting on other people or teams to complete tasks and fewer bottlenecks resulting in less risk of delays or other issues. Additional the more self-sufficient an individual or team is, the easier it is to hold them accountable for their performance.

Conclusion & questions

Regardless of team, company or industry there is always scope for increasing performance. Constraints provide the fastest route to significant improvement and are the foundation for continuous growth.

Knowing your constraints can help in designing quicker, more focused experiments that reduce shipping time and speed up the learning process.

This post was inspired by Conversion Rate Experts article: The Theory of Constraints: How we relentlessly improve our productivity