Decision –

Reevaluation of sec. 3545 prospective only to avoid interfering with units already established under Belmont No. 7 or Petaluma No. 9; pp. 19-20.

Amendments affecting unrelated sections, or even reenactment of language will not be construed to approve or condone an administrative agency's prior erroneous interpretation of a statute; p. 13.

Purpose of statute presumed to be preserved; interpretation should not ascribe to Legislature the commission of a meaningless act; p. 8. Rejected bills have little value as evidence of legislative intent; p. 12.

Reading 3545(b) together with 3545(a) gives rise to the presumption that all teachers are to be placed in a single unit save where the criteria of the latter section cannot be met; the burden of proving the inappropriateness of a comprehensive teachers' unit is on those opposing it; p. 10.

Skills center teachers sufficiently lacking in community of interest to justify exclusion from overall certificated union, as interests of the two groups are sufficiently disparate that the negotiating process might be seriously impeded by internal disruption; pp. 15-19.