Many attempts are currently ongoing to measure or estimate the short fiber content in raw cotton by High Volume Instrument (HVI). Up to now, a fiber is considered "short" if its length is lower than 12,7 mm, even if it is not proven that this is the most efficient number to be taken into consideration for this categorization. We used different tools allowing a comparison between results from AFIS and HVI distributions for different types of materials and cottons. Our conclusions could highlight a technical limit in the HVI technology for measuring that criteria on actual HVI.