Random and non-random selections combined

In doing so, they took into account the problem of non-random selection into the

In reality, it would be much more correct to consider natural selection as the result of two phenomena: undirected mutations and non-random selection.

Put differently, non-experimental evaluations always raise concerns about non-random selection into a program.

The positive impact remains valid even when a possibly non-random selection of firms for government support programmes is controlled for.