WASHINGTON (AP) — A gauge of future economic activity posted an increase in December, providing evidence the economy was gaining strength as the year ended.

The Conference Board says that its index of leading economic indicators rose 0.4 percent last month following a revised 0.2 percent increase in November and a revised 0.6 percent gain in October.

The December report reflects extensive changes in how the index is put together which the Conference Board hopes will make the index a better forecaster of where the economy is headed.

Conference Board economist Ken Goldstein says the December index reading provided support for cautious optimism about how the economy will perform in the first half of 2012.