(a) A good faith effort shall be made, to the extent practicable, to estimate the likely economic cost impact of the guidance document to determine whether the document might be significant. It may, however, be difficult to predict with precision the economic impact of voluntary guidance.

(b) When determining the likely economic cost impact, the same level of analysis should be given as that required for a major determination under the Congressional Review Act (5 U.S.C. 801 et seq.) and the economic impact on small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.).