Evaluation Evaluation is key to building effective and efficient search engines measurement usually carried out in controlled laboratory experiments online testing can also be done Effectiveness, efficiency and cost are related e. g if we want a particular level of effectiveness and efficiency this will determine the cost of the system configuration efficiency and cost targets may impact effectiveness 5/NEvaluation • Evaluation is key to building effective and efficientsearch engines – measurement usually carried out in controlled laboratory experiments – online testing can also be done • Effectiveness, efficiency and cost are related – e.g., if we want a particular level of effectiveness and efficiency, this will determine the cost of the system configuration – efficiency and cost targets may impact effectiveness 5/N