As used in KRS 156.551 to 156.555, unless the context requires otherwise:
(1) "Center" means the Center for Middle School Academic Achievement;
(2) "Fund" means the Teachers' Professional Growth Fund;
(3) "Middle school" means grades five (5) through eight (8), regardless of school or district configuration; and (4) "Reliable, replicable research" means objective, valid, scientific studies that:
(a) Include rigorously defined samples of subjects that are sufficiently large and representative to support the general conclusions drawn;
(b) Rely on measurements that meet established standards of reliability and validity;
(c) Test competing theories, where multiple theories exist; and (d) Are subjected to peer review before results are published.