Whilst well argued this article is a bit disingenuous as it does not deal directly with the research that was actually done in Kenya, only on how it was reported in the Economist.
As the research wrap show (link below) they outcomes of the research were very well defined. The research shows that the unconditional transfers were associated with:
1. 33 percent increase in incomes
2. 53 percent increase in value of household assets
3. Reduction of days without food for children by 42%
1 & 2 are exacly related to Welfare in the way that economists think about Welfare Economics. 3, less so, but is arguably a pretty decent outcome.
The author should engage with this important and interesting research and not poo-poo it based upon how it was reported in a public periodical.