OBJECTIVES: Minimising post-surgery length of stay is important to patients, clinicians and payers who want to optimise recovery rates and minimise costs.  However, evaluating new products and procedures using actual length of stay is influenced by hospital payment  incentives,  organisational structures and socio-economic factors. This study aimed to identify instruments to measure post-anaesthesia home readiness and evaluate their suitability for use in a clinical trial. METHODS: A literature review was carried out to identify published evidence including home readiness instruments. Medline, Embase and Biosis databases were searched for RCTs and instrument-specific publications.  The internet was searched for health technology assessments, economic evaluations and guidelines. An inventory of instruments was compiled and, for each, the suitability of use in a clinical trial setting was assessed in terms of previous examples of use in a clinical trial, evidence of validation and reliability, compatibility with other recovery measures, supporting information and application to an in-patient setting. RESULTS: Fifteen papers provided evidence of the use of the Post-Anaesthetic Discharge Scoring System (PADS) [1] in a variety of trial settings and validation work.  Nine papers referred to other instruments measuring home readiness but no other instrument had been used in more than one trial or validated.  The British Association of Day Surgery referred to PADS in their published guidelines.  There was an example of PADS in an economic evaluation of fast-tracking recovery [2]. CONCLUSIONS: PADS was found to be the most appropriate instrument for assessing home readiness as it has undergone more validation than other identified measures and there is evidence of its use in multiple RCTs. [1] Chung et al.  A post-anesthetic discharge scoring system for home readiness after ambulatory surgery.  Journal of Clinical Anesthesia 1995;7:500-6; [2] Song et al.  Fast-tracking (by-passing the PACU) does not reduce nursing workload after ambulatory surgery.  Br J Anaesth 2004;93:768-4.