(MONEY Magazine) – Forget for a moment the issue of Social Security's future solvency. Today the agency is facing a challenge over the accuracy of its records -- which ultimately determines whether you will get all the benefits you earned. Recent studies by the U.S. General Accounting Office have detected benefit- threatening errors in many individual cases. In one sample, the benefits were wrong for one out of six cases. The key GAO findings: -- Social Security may not have credited as many as 9.7 million Americans with their full earnings from 1978 to 1984, mainly because of wage-reporting conflicts involving the agency, the IRS and employers. In a GAO sample of Social Security beneficiaries with uncredited earnings, 25% were being shortchanged an average of $17 a month (the average loss over time: $456). -- Social Security may have over- or underpaid an average of 4.7 million beneficiaries from 1981-86. In a GAO survey of cases from 1984, the errors had remained on individuals' records for an average of five years, with a cumulative underpayment of $591 and overpayment of $1,069. Though the agency is reviewing cases to find errors, you may want to double- check your own situation, even if you are still working. High-risk groups for errors include the self-employed, frequent job switchers, people who work for companies with fewer than 15 employees and pensioners who return to work temporarily. To verify your recent records, send in a card designed for that purpose: ''Request for Statement of Earnings,'' Form SSA-7004, which you can obtain by calling, visiting or writing your local Social Security office. Within four to six weeks after you send the card, you will receive a year-by-year listing of your earnings from 1983 through 1986 and a lump-sum total for your career. If the 1983-86 figures match those in the ''Social Security wages'' line on your old IRS W-2 forms, your latest records are accurate. If you see a discrepancy, alert your Social Security office. When the error is evidently clerical -- a transposed digit, for instance -- you need do no more than point it out. Beyond that, however, you must supply documentary proof of your case, usually a copy of your W-2 for the year in question. For a longer-term verification (as far back as 1951), you need the full- fledged but simple-to-complete Form SSA-7050, the ''Request for Social Security Earnings Information.'' Get it from your local Social Security office. Check off the box labeled ''Total earnings for each year'' and list the years you want. Within two to three months you will receive a list of your annual earnings. Again, compare the amounts with the totals on your back W-2s and call your local Social Security office if you can prove a discrepancy. (Though the agency warns about a three-year statute of limitations for corrections, you can in fact get the record changed for any error you can prove. For evidence, however, you will need your old W-2s. The IRS does not store them, and employers aren't required to keep them on file for more than four years. So beyond that, you're out of luck without a W-2.) By midyear, Social Security plans to streamline the record-requesting procedure by introducing a ''personalized benefit statement,'' available upon request, that lists all your annual earnings and estimates your retirement benefits. Also, the agency is considering a new automatic reporting program for beneficiaries, all of whom would be mailed an annual statement of their individual benefits to date. If you are receiving Social Security benefits and want to verify them, ask your local office's claims representative to get your earnings records and review them with you just as you did when your benefits started. Again, the burden of proof of error is on you. Ask the representative also to refigure the computation of your benefits. For comparison, you can reckon roughly what your benefits should be by getting the agency's pamphlet, Estimating Your Social Security Retirement Check, and filling in the worksheet. If all this investigation happens to show you are being overpaid, your luck may not be all bad. A later general audit might have revealed faulty math anyway.

CONGRESS KEEPS ITS WORD-FOR NOW Tax reform lives! Despite the glowering federal budget deficit, Congress not only kept its promise to cut individual tax rates in 1988 to their lowest level in more than 50 years but surprisingly decided against raising excise taxes or pilfering more deductions from individuals -- at least for now. As Money went to press, the Senate and House of Representatives were negotiating a final package of tax changes to raise a paltry $9 billion to help trim next year's deficit to $145 billion. The only tax provision that will likely affect you is an extension of the 3% excise tax on telephone service. Other changes will, for the most part, have even less impact on smaller segments of the population. For example, beginning in 1988, you will no longer be able to count the cost of sending a youngster to an overnight camp toward the child-care credit. But such expenses still qualify for the credit -- a maximum of $720 for one child -- on your '87 tax return, provided the child is under 15 and you and your spouse both work. The new law will almost certainly diminish the appeal of master limited partnerships, or MLPs, which are income-producing investments trading on the major stock exchanges. Investors with nondeductible tax-shelter losses will be prohibited from salvaging the write-offs by claiming them against income from MLPs. Curtailed tax-shelter deductions will be able to offset only income from limited partnerships that are not publicly traded, thereby excluding MLPs. The provision would be retroactive to the beginning of 1987.