however because these are demographic variables that hardly vary over the short term their disaggregate analysis is omitted the survey year used differs from country to country the period refers to the survey nearest to that year the period to the survey available nearest to and and the period to surveys available between and in the countries that saw the greatest poverty reduction the workforce grew in tandem with higher labour income per employed person while in the other countries that was not the case a simple way to illustrate these differences is to compare the poverty rate of a group of persons with a given trait with others who do not share that trait