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  • Jo Clubb

Mini: Bottlenecks

In Farnam Street’s Great Mental Models Volume 3 (Systems and Mathematics), bottlenecks are presented as a model to demonstrate how a limiting factor can potentially hurt a system.


Bottlenecks are inevitable. Every system will have a point that most limits its efficiency. However, it is the magnitude of the bottleneck that is of most interest. If the bottleneck is causing excessive strain or resource waste behind it, action should be taken to address it.


Yet, we need to be cautious in creating another, potentially worse, bottleneck elsewhere in the system. Take action with non-naïve interventionism by considering the knock-on effect to other parts of the systems.


Bottlenecks During Athlete Screening

When I think about bottlenecks, I think of athlete screening. Particularly day one of preseason. To many practitioners, this is our Super Bowl! We have limited time to get an entire squad through all of the tests, while maintaining validity and reliability in the testing process. There will be a bottleneck somewhere in the system.


An excessive bottleneck is a threat to the screening process in a number of ways. It may lead to athletes cooling down in-between tests, reducing their performance and increasing injury risk. It can reduce their interest and motivation, once again reducing testing outcomes, or potentially them wandering off and slipping through the net altogether!


A bottleneck may also cause deleterious on-the-spot adjustments. Perhaps we reduce the number of trials we are collecting, affecting testing precision. Alternatively, practitioners may feel under pressure to reduce or remove athlete feedback. While this may save time and reduce the bottleneck, feedback is a vital part of the process and an in-situ conversation may be the best, or only, option to do so.


Three steps we can take to try to reduce the bottleneck effect:


  1. Establish the constraints. These are different to a bottleneck. According to FS; “a bottleneck is something we can alleviate; a constraint is a fundamental limitation of the system”. In our context, these will include how many athletes and stations you have, and potentially how much time has been allocated to screening.

  2. Simulate conditions. Do a run-through of the screening process. One individual will not replicate 25 or 90 athletes, but can provide an estimate of timings and flow.

  3. Anticipate where the bottlenecks will come and plan accordingly. With your prior experience plus the run-through, identify the station(s) that may cause the greatest bottleneck. Plan the station order with this in mind. Create a Plan B (and C!) to revert to if needed.


Although bottlenecks give us headaches, they can also lead to innovation. Just because you’ve “always done it this way”, doesn’t mean it has to endure. Maybe a disproportionate bottleneck is a sign to change your mind and think again.