AFTERSHOCK: After China reported first-quarter economic growth of 7.7 percent, slower than traders expected, a global market plunge wiped billions of dollars off stock prices.
RELIABILITY CONCERNS: Traders had relied on other Chinese government data in shaping their forecasts for first-quarter growth. Some analysts say the other data may have been inflated. Many companies are skeptical of government numbers. But investors attach huge importance to data on the performance of the world's second-largest economy.
MORE RESOURCES: The government still is the only source for most nationwide data, but a growing number of banks and research firms are developing their own based on surveys of companies and consumers.