In a working paper circulated by the National Bureau of Economic Research, academics MS. Carpenter, Fangzhou Lu and Robert F. White law used a gauge called"price informativeness" to look at how accurately share prices in China could predict corporate earning. They found that the measure started improving when China joined the world trade organization in 2001. It gained more in subsequent years as market overhaul were rolled out, with a pickup in 2005 when authorities allowed the public to access a large portion of the market previously held only by privileged share holder such as the state.