The time it takes to generate attribution results depends on the time it takes to capture an adequate volume of observations to yield statistically significant results. On average, it takes Convertro's algorithm an approximate 1,000 conversions and at least 100 marketing exposures to deliver accurate results. The algorithm is able to build attribution weights for all the sources but for sources with low volumes the confidence will be comparatively lower than other sources. Our attribution weightings are applied only for the level of granularity where we have enough confidence in the weighting. For example, if there are very few observations of a keyword in the data set (with therefore low confidence in the weighting), the attribution weighting applied will be that of the “subchannel” level - in this case, the search engine.