Complex sentence: Booth was critical of the existing statistical data on poverty, by analysing census returns he argued that they were unsatisfactory and later sat on a committee in 1891 which suggested improvements which could be made to them.
Split into simpler sentences: Booth was critical of the existing statistical data on poverty. By analysing census returns he argued that they were unsatisfactory and later sat on a committee in 1891 which suggested improvements which could be made to them.