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Hey Max, *imr is the "raw" internal MozRank value. The "pretty" value that most people use for their applications is *imp, which has been fit to a nice 0-10 scale. *imr isn't an official data point in the API, just meaning we reserve the right to change as necessary, which is why we don't have it documented. However, we still return the value if you know the endpoint Hope that helps! Let me know if you have more questions! Thanks, Carin