Stock index futures turned positive on Thursday after data on weekly jobless claims and worker productivity.

S&P 500 futures rose 0.5 point and were about even with fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures added 13 points, and Nasdaq 100 futures gained 3 points.

(Reporting by Chuck Mikolajczak)