A Richtwert is a benchmark or reference value. I think benchmark value chart gets the idea across.
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This test examines Value Model’s performance in each of the following areas:
- Its ability to deliver a value conclusion (“hit rate”).
- The variance, or difference, between the model’s estimates of value and a benchmark value,
in this case the property’s sales price.
- The dispersion of the differences between the value estimates and the benchmark values.
Dispersion is expressed as standard deviation from the mean, and can be plotted in a
histogram.
- The model’s tendency to consistently under- or over-value property.

http://rers.thewarrengroup.com/avm/help/value_model_test_res...