The economy should grow about 5 per cent in 1978, as measured by the so-called real gross national product (the total goods and services produced by the economy). Jobs

The dramatic decline in December's joblessness sent forecasters scurrying back to their computers. At 6.4 per cent at the end of 1977, below the administration's old goal for 1978, some optimists now think the jobless rate could fall below 6 per cent by the end of 1978. Prices

Consumers prices will probably climb about as fast as in 1977, when they jumped more than 6.5 per cent. Retail prices will rise between 6 and 6.5 per cent in 1978 and may be accelerating by yearend. Taxes

President Carter will soon propose a tax reduction of about $25 billion, about $15 billion for individuals, $7 billion for business and the rest excise taxes, to take effect Oct. 1. Interest

Short term interest rates, which have been rising in recent weeks, can be expected to rise further in 1978 as demand for funds continues to rise. Long-term rates, such as those on mortgages, will also rise. Wages

Wage increases should continue right along in the 7 to 8 per cent rut they have been stuck in for several years.