For a 5-point rating scale:
*Please note the interpretation guide does not consist of rigid rules, but merely reasonable recommendations.
Margin of ErrorMargin of Error (%)Interpretive Validity*
Less than 0.12Less than ± 3%Excellent interpretive validity
Between 0.12–0.20Between ± 3-5%Good interpretative validity
Greater than 0.20Greater than ± 5%Questionable interpretative validity; values should be interpreted with caution

Example at NC State University: