Simplify the following text for a Grade 24 native English-speaking person.
Original: The following are common criticisms directed at the HDI : that it is a redundant measure that adds little to the value of the individual measures composing it ; that it is a means to provide legitimacy to arbitrary weightings of a few aspects of social development ; that it is a number producing a relative ranking which is useless for inter-temporal comparisons , and difficult to compare a country 's progress or regression since the HDI for a country in a given year depends on the levels of , say , life expectancy or GDP per capita of other countries in that year .
Simplified: The HDI has been criticized as a redundant measure that adds little to the value of the individual measures composing it ; as a means to provide legitimacy to arbitrary weightings of a few aspects of social development ; as a number producing a relative ranking which is useless for inter-temporal comparisons , and difficult to compare a country 's progress or regression because the HDI for a country in a given year depends on the levels of , say , life expectancy or GDP per capita of other countries in that year .