[ , , ] Answer the previous question again, but this time rather than using the earlier observational study by Kramer (2012), use the results from an earlier natural experiment by Lorenzo Coviello et al. (2014).
[ , , ] ຕອບຄໍາຖາມກ່ອນຫນ້ານີ້ອີກເທື່ອຫນຶ່ງ, ແຕ່ເວລານີ້ແທນທີ່ຈະໃຊ້ການສຶກສາສັງເກດກ່ອນໂດຍ Kramer (2012), ນໍາໃຊ້ຜົນໄດ້ຮັບຈາກການທົດລອງທໍາມະຊາດກ່ອນໂດຍ Lorenzo Coviello et al. (2014).