A census block group map may not accurately represent the customer base of downtown retailers and restaurants. In fact, the numbers are so different from one census block group to the next, that it is often impossible to determine if a neighborhood is truly representative of its population. This is especially true when looking at the population of different areas within the same city. Although the U.S. Census Bureau does their best to control the number of households in each block group, wide variations can still occur. Whether people live in smaller or larger areas and the household sizes are correlated can affect the results of this information.