File:Recall metric.jpg

Figure: R-Metric graph demonstrates superiority of Algorithm SM-18 over the old Algorithm SM-15 for the presented collection used in the testing period of full 4 years dating back to Apr 2, 2015. It was plotted using 24,104 data points (i.e. repetition cases with data from both algorithms), and smoothed up to show the trends. Multiple spots beneath the line of 0 at the vertical axis (R-metric<0) have been smoothed out (they correspond with days when the previous version of the algorithm appeared superior in a smaller sample of repetitions). Some positive and negative trends correspond with changes in the algorithm as data were collected in the new algorithm's testing period. A gradual increase in the metric in the months Feb-May 2016, might be a statistical aberration, or it might be the result of new interval values and a bigger R-metric for intervals departing from the optimum used in earlier SuperMemos. The latter interpretation might suggest that the benefits of Algorithm SM-18 can gradually increase over time