Labor productivity at American businesses other than farms rose at a seasonally adjusted annual rate of 2 percent in the fourth quarter of 1982 but only a scant 0.1 percent for the year as a whole, according to revised figures reported yesterday by the Labor Department.

The fourth-quarter gain, which earlier was put at a 2.7 percent rate, brought the annual average back only to the same level as in 1977. The increase for the quarter was down from a 3 1/2 percent rate in the third quarter, when output rose slightly while the number of hours worked declined. In the last quarter, hours worked fell faster than output.

Meanwhile, the Commerce Department said that spending for construction rose to a seasonally adjusted annual rate of $255.5 billion in January, up 8.9 percent from December for the largest monthly increase since 1946. Outlays had fallen 4.7 percent in December to climax a year in which they dropped at the fastest pace since World War II.

Private construction spending climbed 7.1 percent to a $200.2 billion rate; public construction outlays, 15.9 percent to a $55.3 billion rate. Together, they were 13 1/2 percent higher than in January 1982.

Significant increases were registered in single-unit homes, up 17.8 percent to an annual rate of $47.7 billion; retail and other nonoffice, nonindustrial commercial buildings, up 19 percent to $16.2 billion; government-financed housing and redevelopment, up 37 1/2 percent to $2.2 billion; and highways and streets, up 18 1/2 percent to $14.7 billion.

The Labor Department said that the productivity gains in the second half of 1982 were accompanied by increases in compensation paid per hour of 6.6 percent in the third quarter and 5.6 percent in the fourth. That resulted in an increase in unit labor costs--one of the major factors influencing the rate of inflation--at a 3.1 percent rate in the third quarter and a 3 1/2 percent rate in the fourth.

For the year as a whole, unit labor costs rose 7.1 percent, down from 8.1 percent in 1981. However, nonlabor payments, which rose 13.1 percent in 1981, increased only 3.2 percent last year. That sharp decline, coupled with reduced profit margins caused by the recession, reduced inflation in the nonfarm business sector from a 9.7 percent rate in 1981 to a 5.8 percent rate last year.

Some analysts, such as economist John Kendrick of the American Enterprise Institute, believe the economic recovery now under way should produce substantial productivity gains this year, perhaps as much as 3 1/2 percent for the entire business sector. That is still below the 4.7 percent average gain in the first year of postwar recoveries.

But if compensation increases remain at about the level of the fourth quarter, the combination could mean a rise in unit labor costs in the neighborhood of 2 percent. And that would be the best performance of that indicator since 1965--at least as far as inflation is concerned.