; and (B) if the determination is positive, validate the certification. (c) Improvements in compliance with building energy codes (1) Requirement (A) In general Not later than 3 years after the date of a certification under subsection (b), each State and Indian tribe shall certify whether or not the State and Indian tribe, respectively, has— (i) achieved full compliance under paragraph (3) with the applicable certified State and Indian tribe building energy code or with the associated model building energy code; or (ii) made significant progress under paragraph (4) toward achieving compliance with the applicable certified State and Indian tribe building energy code or with the associated model building energy code. (B) Repeat certifications If the State or Indian tribe certifies progress toward achieving compliance, the State or Indian tribe shall repeat the certification until the State or Indian tribe certifies that the State or Indian tribe has achieved full compliance, respectively. (2) Measurement of compliance A certification under paragraph (1) shall include documentation of the rate of compliance based on— (A) independent inspections of a random sample of the buildings covered by the code in the preceding year; or (B) an alternative method that yields an accurate measure of compliance. (3) Achievement of compliance A State or Indian tribe shall be considered to achieve full compliance under paragraph (1) if— (A) at least 90 percent of building space covered by the code in the preceding year substantially meets all the requirements of the applicable code specified in paragraph (1), or achieves equivalent or greater energy savings level