Millions of older people face shrinking Social Security checks next year, the first time in a generation that payments would not rise. The trustees who oversee Social Security are projecting there won’t be a cost of living adjustment (COLA) for the next two years. That hasn’t happened since automatic increases were adopted in 1975. By law, Social Security benefits cannot go down. Nevertheless, monthly payments would drop for millions of people in the Medicare prescription drug program because the premiums, which often are deducted from Social Security payments, are scheduled to go up slightly.