New Erb & Harvey study on the drivers of <a href="https://twitter.com/hashtag/gold?src=hash&ref_src=twsrc%5Etfw">#gold</a> prices. On ETFs, China, Costco buyers, and difficulties with finding reliable data. Correlation or causation? <a href="https://twitter.com/jsblokland?ref_src=twsrc%5Etfw">@jsblokland</a> <a href="https://twitter.com/camharvey?ref_src=twsrc%5Etfw">@camharvey</a> <a href="https://t.co/zsioCcNr5S">https://t.co/zsioCcNr5S</a> <a href="https://t.co/twyFuhRTF6">pic.twitter.com/twyFuhRTF6</a>