An evaluation of the difference in the demand and supply of space (measured in terms of square footage) for a particular type of commercial property in a given market area where gaps are expressed as the amount of square footage demanded less the amount of square footage available in a given time period.  Note that if demand exceeds supply, the gap will be positive.  A positive gap indicates that potential opportunities exist for successful commercial real estate transactions.  However, transactions might be avoided when supply exceeds demand (or when a negative gap occurs), as there is an oversupply of available space in the market.