The ironic part about this is that companies think this is a benefit to the employee, when in reality this seems to be a classic example of the psychological anchoring bias that influences people to take LESS vacation. For those who aren't familiar, this is a well established psychological heuristic that says our decisions are heavily influenced by some 'anchoring' information, in this case, the number of vacation days allowed.
I'm heavily paraphrasing Kahneman here, but numerous experiments have shown this effect in a variety of ways. Perhaps most counterintuitively, in an experiment where an arbitrary limit was set on the purchase of soup on sale, the amount of soup people bought was twice what was bought when no arbitrary limit was set. I'm not aware of any empirical studies examining this with vacation days, but anecdotal evidence like this seems to support the influence of this effect. I'd be extremely interested to see the data on the number of vacation days taken by employees at the no set vacation companies vs. others.
I'm heavily paraphrasing Kahneman here, but numerous experiments have shown this effect in a variety of ways. Perhaps most counterintuitively, in an experiment where an arbitrary limit was set on the purchase of soup on sale, the amount of soup people bought was twice what was bought when no arbitrary limit was set. I'm not aware of any empirical studies examining this with vacation days, but anecdotal evidence like this seems to support the influence of this effect. I'd be extremely interested to see the data on the number of vacation days taken by employees at the no set vacation companies vs. others.