when using dso to compare the cash flows of a number of companies you should compare companies within the same industry with similar business models and revenue numbers if you try to compare companies in different industries and of different sizes the results you ll get will be misleading because they often have very different dso benchmarks and targets 
dso is not particularly useful in comparing companies with significant differences in the proportion of sales that are made on credit the dso of a company with a low proportion of credit sales does not indicate much about that company s cash flow comparing such companies with those that have a high proportion of credit sales also says little in addition dso is not a perfect indicator of a company s accounts receivable efficiency fluctuating sales volumes can affect dso with any increase in sales lowering the dso value delinquent days sales outstanding ddso is a good alternative for credit collection assessment or for use alongside dso like any metric measuring a company s performance dso should not be considered alone but rather should be used with other metrics 