Not Enough Meaning
We simplify probabilities and numbers to make them easier to think about
Subadditivity effect
Description
The tendency to judge the probability of the whole to be less than the probabilities of the parts.
Subadditivity effect in business decision
When estimating project costs, the sum of estimates for individual tasks might be perceived as less than an overall holistic estimate of the entire project, potentially leading to underestimation.
Subadditivity effect in personal life decision
You estimate the total time required for several errands separately and then add them up, underestimating the overall time needed.