To interpret the Human Development Index (HDI) of North America, Central America, and the Caribbean accurately, the factor that must be considered is:
Canada and the U.S. have significantly higher scores than the rest of the countries.
This is important because the high HDI scores of Canada and the U.S. can skew the overall average HDI for the region, making it appear higher than it may be when considering the HDI scores of other countries in Central America and the Caribbean, which tend to be lower.