Indeed, almost any investigation is likely to lead to results conditional on a range of alternative assumptions.

Thus, we may use the models discussed in previous sections to evaluate the possible consequences of alternative assumptions and to suggest different approaches.

In addition to the principal (main) projection, the variant projections available for comparison are based on alternative assumptions of future fertility, mortality and migration.

Such models may be devised in order to depict the essential quantitative impact of alternative assumptions or government policies.

However, alternative assumptions can be made.

The analysis can be made more sophisticated, and sometimes more realistic, by introducing alternative assumptions relating to country size.

Let us, for the sake of discussion, entertain the alternative assumption that life has arisen only once, ever, and that was here on Earth.

To understand why it is, consider an alternative assumption.

Pechman's study attempts to show what difference alternative economic assumptions about the incidence of various taxes make.

Exploring the implications of alternative assumptions is likely to lead to better policy than making a single blanket recommendation.