Two research practices have held back the development of an adequate factual base for population ethics.

One practice begins with conclusions & then selects only those facts consistent with them. Analysts claiming that rapid population growth has had negative consequences for economic development often cite facts supporting that conclusion & leave out contrary evidence. Those claiming benefits from rapid population growth do the same.

The second practice involves assigning more or less weight to population conditions than objective research would support. Some advocates of fertility control claim that rapid population growth has caused starvation & political instability in the developing countries. Such simple interpretations overlook the many other influences leading to those conditions, such as the lack of food in poor countries, corruption among political leaders, & ethnic conflicts.

Both methods cannot provide solid explanations for major problems in for population ethics.