EMPLOYED WOMEN won an important victory in the Supreme Court this week when the justices ruled in Arizona v. Norris that Title VII of the Civil Rights Act prohibits an employer from offering a pension benefit plan that discriminates on the basis of sex. Although 90 percent of all workers are covered by plans that provide benefits without regard to sex--employees of the federal government and most large corporations fall into this category-- some plans, in particular those provided by local governments and nonprofit organizations, pay a lower monthly benefit to women because women generally live longer than men and will therefore receive benefits for a longer period of time. This kind of employer plan will no longer be allowed.

While women's groups are justifiably jubilant about the decision, employers and insurance companies can make adjustments and live with the new rules too, because the decision is not retroactive. In recent testimony before the Senate Commerce Committee, insurance industry executives said that a decision exactly like the one the court has just made "would not be unreasonable." It is important that the court refused to apply the ruling to persons already retired or to contributions already made, because such a requirement would create enormous unfunded liabilities that could jeopardize the stability of many pension funds. Thus only benefits derived from contributions made after the date of the Supreme Court's judgment must be calculated without regard to the sex of the employee.

The Norris case does not settle all questions of sex- based insurance rates. In fact, the court emphasized that this decision on employment practices does not deal with the larger issue of whether consideration of sex should be prohibited in all insurance contracts. Employers of fewer than 15 people, for example, are not covered by Title VII and are not affected by the decision. Group health and disability policies are priced according to the past experience of the group being covered, a practice that would not be changed by the decision. And policies purchased by individuals rather than employers--annuities, life insurance, automobile insurance and individual health policies, for example--may still vary in price according to sex if such distinctions can be actuarially justified.

Congress is now considering legislation that would outlaw sex differentials in all insurance. It is a sweeping, controversial measure that will be fought hard by the industry. But this week, the issue that had the broadest public support and was of primary importance to the women's movement was settled. The law requires that men and women receive not only equal pay, but equal pensions for equal work.