HONG KONG — The pace of growth in China’s economy accelerated last year for the first time in seven years as exports, construction and consumer spending all climbed strongly.

At least, that’s what the government says.

In reality, the pace of growth in China’s economy is anybody’s guess. Various signals suggest China’s growth did speed up last year, which could give the government the room it needs to tackle an accumulation of serious financial, environmental and social problems this year.

But measuring the size and health of the world’s second-largest economy can be difficult at best. Its official figures have become implausibly smooth and steady, even as other countries post results with plenty of peaks and valleys. Officials in far-flung regions are admitting their numbers are wrong. And outside experts crunching the data have come up with different — and usually weaker — results.