HN user btilly has a really helpful essay on the math behind stopping tests earlier than your predetermined sample size. It calls for setting a maximum duration

HN user btilly has a really helpful essay on the math behind stopping tests earlier than your predetermined sample size. It calls for setting a maximum duration, and provides stopping points along the way. Works similar to the method AirBnB describes. http://elem.com/~btilly/ab-testing-multiple-looks/part2-limited-data.html http://elem.com/~btilly/ab-testing-multiple-looks/part2-limi...