Brian, the algorithm is a grey box to most of us, we are told the rough dimensions but not the specifics. Medium does mention that time spent reading is an important factor in determining payout, along with other engagement metrics. They have an approximate way of determining if your readers spent on average 2 minutes on one, and 5 on another piece, and they will reward the latter. Which is of course a function of the length of the piece as well as also how engaging it is. Also, in your example, if the first piece had twice the readers applauding but fewer overall claps (assuming for the sake of argument equal time spent reading) I would not be surprised if Medium rewarded the first more. Number of people responding is a tangible, concrete thing — how much each claps is more ephemeral & loosey-goosey.