Alternatively, you could just guesstimate it. Dead serious, that’s the best description of the procedure at the Bureau of Labor Statistics. Referring to Bils and Klenow here, 46% of the time they simply say that a new good is comparable to old good and make no quality adjustment, 22% they either use hedonic pricing or the manufacturer’s estimate of how much it cost to make, and for the remainder it says that the quality adjusted price is whatever is necessary to make its inflation for that month the same as the other goods in its narrow category. This can lead to obvious silliness – when Walmart entered markets, offering goods at cheaper prices than traditional grocery markets, the BLS didn’t actually notice this as a price change at all.