Answer:
they do not include the price of assets.
Step-by-step explanation:
Standard Goods Market Price Index often shortened as SGMPI is a term that describes a standard mode of measuring price index, which is used to illustrates the price position of only goods in comparison to other top competitive goods in similar classifications and brands.
Hence, in this case, the usefulness of standard goods market price indexes for judging policy is limited because: "they do not include the price of assets."