- Israel has the highest fertility rate in the developed world (3.1 children per mother on average)
- The average gross monthly salary at the time of the study was NIS 5,595
- If the average parent comes late 4 times a month, that's 4 * 3.1 * 10 = NIS 124 = 2.2% of their monthly salary, or the majority of an entire day's pay (!) - that's not nothing.
That said, there are two interesting conclusions from the paper. Firstly, the well known one:
> Parents may have interpreted the action of the teachers in the first period as a generous, nonmarket activity. They may have thought: "The contract with the day-care center only covers the period until four in the afternoon. After that time, the teacher is just a nice and generous person. I should not take advantage of her patience." The introduction of the fine changes the perception into the following: "The teacher is taking care of the child in much the same way as she did earlier in the day. In fact this activity has a price (which is called a ‘fine’). Therefore, I can buy this service as much as needed."
But there's also this:
> The behavior in the third period, however, is still difficult to explain. Now the first social norm would predict a low level of delay. We may think that a period of 4 weeks is not sufficient to bring the behavior back to the appropriate level. But considering that 2 or 3 weeks had been enough to double the level of delays after the introduction of the fine, we should estimate that the learning rate of the parents is too fast to justify so much inertia. Perhaps a third social norm is needed: "Once a commodity, always a commodity." This norm and second clause of the first norm explain the behavior in the final period: a commodity at zero price is bought in large quantities. Overall, three norms seem necessary to explain three facts.
What I do know is that I completely respect snarf21's choice to either charge or not as they see fit.
If you charge people for something, it kicks their perception of the act into a different category. That in turn effects how they think about the interaction and what their sense of entitlement and expectations are in ways that can be counter-intuitive.
A famous related study is: https://freakonomics.com/2013/10/23/what-makes-people-do-wha...
They found that when daycares fined parents for picking up their kids late, the result was parents picking them up even later. Because, without the fine, parents treated the pick-up time as a moral/social obligation that they did not want to uphold. Once the fine was introduced, they treated this as a simple financial transaction where if it's worth it to pay the extra to pick them up later, why not?