Time-Saving Bias
The Psychology Behind It
Here is a puzzle: Who saves more time?
- Driver A increases their speed from 20 mph to 30 mph over a 10-mile trip.
- Driver B increases their speed from 50 mph to 60 mph over a 10-mile trip.
Most people intuitively feel that Driver B saves more (or the same), because they are going faster. In reality:
- Driver A goes from 30 mins to 20 mins. Saved: 10 minutes.
- Driver B goes from 12 mins to 10 mins. Saved: 2 minutes.
We fail to realize that the relationship between speed and time is not linear; it follows a 1/x curve. The time savings are massive at low speeds and diminishingly small at high speeds. Yet, we obsess over driving 80 mph instead of 70 mph to "make up time," risking tickets and accidents for negligible gain.
Real-World Examples
Highway Driving
Drivers often speed aggressively to "save time," weaving through traffic to go 85 mph instead of 75 mph. Over a 20-mile commute, this saves less than 2 minutes, but significantly increases fuel consumption and accident risk.
Manufacturing
Managers might focus on speeding up a machine that is already fast (e.g., 1000 units/hour to 1100 units/hour) rather than fixing a bottleneck machine that is slow (e.g., 10 units/hour to 20 units/hour). The gain from the slow machine is far greater.
Healthcare processes
Improving a slow manual intake process (low speed) saves far more total patient time than shaving seconds off a rapid automated scan (high speed).
Consequences
The time-saving bias can lead to:
- Dangerous Driving: Unnecessary speeding that risks lives for seconds of gain.
- Inefficient Optimization: Focusing resources on the wrong part of a process.
- Frustration: Drivers get angry at slow traffic, not realizing that going 40 mph instead of 60 mph only adds a few minutes to their trip.
How to Mitigate It
Do the math.
- Calculate the Minutes: Don't trust your gut. Use the formula
Time = Distance / Speed. Calculate the difference. - Focus on the Slow: In any system (traffic, factory, code), the biggest gains come from improving the slowest parts, not speeding up the fastest parts.
- Relax on the Highway: Realize that the stress of speeding is not worth the 3 minutes you might save.
Conclusion
The time-saving bias is a failure of our linear intuition in a non-linear world. By understanding the math of speed, we can make safer, calmer, and more efficient choices.