Apart from the methodological limitations already declared, the
paper considered a database dealing with peer-reviewed literature,
only. Several development projects and national programmes,
especially in LMICs, do not produce these kinds of papers, or they
do, but some years after. Thus the analyses are not exhaustive.
However, the intention was not to cover every document on the
issue. Indeed, this would be impossible. Rather the aim was to use
the same set criteria to examine a snap shot of countries from
across a range of factors (e.g. geography and economic development).
Use of databases such as PubMed and the inclusion of factors
such as wastewater while useful, would have introduced further
complications, in that while the breath of topics may have
increased, their evaluation would have had to be compromised in
keeping with the word count of the journal.