This gave us the percentage of the nutrients and other substances found in the organically produced foodstuff above or below that found in the conventionally produced foodstuff, and enabled us to combine results from different studies for statistical analysis. Positive differences suggested that there might be more of particular nutrients and other substances in organically produced foodstuffs, negative differences suggested that there might be more of particular nutrients and other substances in conventionally produced foodstuffs. We represented the differences on dot plots by study type, omitting extreme values (defined as values where the absolute difference from the next.
