Timothy Taylor has a superb blog post on that topic, here is one choice passage out of many:
A final example looks at mental models that development experts have of the poor. What do development experts think that the poor believe, and how does it compare to what the poor actually believe? For example, development experts were asked if they thought individuals in low-income countries would agree with the statement: “What happens to me in the future mostly depends on me.” The development experts thought that maybe 20% of the poorest third would agree with this statement, but about 80% actually did. In fact, the share of those agreeing with the statement in the bottom third of the income distribution was much the same as for the upper two-thirds–and higher than the answer the development experts gave for themselves!