RevPAR Index, also called RGI or RevPAR Generation Index, is a property's RevPAR measured against its competitive set. It's how a property finds out whether a good month was its own doing or the whole market's.
RevPAR Index = (Your RevPAR / Comp set RevPAR) x 100
A score of 100 means a property captured exactly its fair share of the market. Above 100 means it took more than its share, and below 100 means it left some on the table.
A property running $120.00 RevPAR against a comp set at $100.00 has a RevPAR Index of 120, so it earned 20% more per available room than its competitors did.
This is the metric that survives a bad market. RevPAR falling 10% while the comp set falls 15% is a share gain, and reading the absolute number on its own would have you fixing something that isn't broken. It cuts the other way too: a record month in a market that grew faster than you did is a share loss.
Index data usually comes from a benchmarking service such as STR, and it's only as good as the comp set behind it. A mismatched set of competitors produces a confident, useless number, so the set is worth arguing about before the index is worth trusting.
Work out the underlying figure with the RevPAR calculator.