Evaluation Measures easures for a search engine All of the preceding criteria are measurable: we can quantify speed /size we can make expressiveness precise The key measure: user happiness What is this? Speed of response size of index are factors But blindingly fast, useless answers wont make a user happy Need a way of quantifying user happinessEvaluation 5 Measures for a search engine ▪ All of the preceding criteria are measurable: we can quantify speed/size ▪ we can make expressiveness precise ▪ The key measure: user happiness ▪ What is this? ▪ Speed of response/size of index are factors ▪ But blindingly fast, useless answers won’t make a user happy ▪ Need a way of quantifying user happiness Measures