Commerce: Market Efficiencies
“Price dispersion is a manifestation—and, indeed, it is
the measure—of ignorance in the market” (Stigler, 1961)
®Badiane and Shively (1998)  on Ghana: “…the estimated time to fully transmit a price shock to each of two outlying markets is about four months.” ®China: accurate price information (via phone) can increase farmer revenue by 60% and improve regional productivity.
Example on right one of many studied where ability to compare prices in village and ‘big city’ via phone not only resulted in lower average price to the consumer, but resulted in significantly lower variation in prices as well.