Institutional Shareholder Services will establish corporate governance ratings for companies included in the Russell 3000 index, according to Patrick McGurn, vice president and director-corporate programs. ISS will rate the companies corporate governance practices on a scale of zero for the worst to 100 for the best. The ratings will give investors a quantitative basis for comparing companies on corporate governance. ISS criteria will include such policies as executive compensation, terms of directors, independence of directors and shareholder rights. ISS expects to unveil the ratings in May or June.