Objective The aim of the present study was to provide a summary of a systematic review of literature reporting benefits and limitations of implementing National Emergency Access Target (NEAT), a target stipulating that a certain proportion of patients presenting to hospital emergency departments are admitted or discharged within 4h of presentation. Methods A systematic review of published literature using specific search terms, snowballing techniques applied to retrieved references and Google searches was performed. Results are presented as a narrative synthesis given the heterogeneity of included studies. Results Benefits of a time-based target for emergency care are improved timeliness of emergency care and reduced in-hospital mortality for emergency admissions to hospital. Limitations centre on using a process measure (time) alone devoid of any monitoring of patient outcomes, the threshold nature of a time target and the fact that currently NEAT combines the measurement of clinical management of two very different patient cohorts seeking emergency care: less acute patients discharged home and more acute patients admitted to hospital. Conclusions Time-based access targets for emergency presentations are associated with significant improvements in in-hospital mortality for emergency admissions. However, other patient-important outcomes are deserving of attention, choice of targets needs to be validated by empirical evidence of patient benefit and single targets need to be partitioned into separate targets pertaining to admitted and discharged patients. What is known about the topic? Time targets for emergency care originated in the UK. The introduction of NEAT in Australia has been controversial. NEAT directs that a certain proportion of patients will be admitted or discharged from an emergency department (ED) within 4h. Recent dissolution of the Australian National Partnership Agreement (which provided hospitals with financial incentives for achieving NEAT compliance) has prompted a re-examination of the 4-h rule, the evidence underpinning its introduction and its benefits and risks to patients What does this paper add? This paper is executive summary of key findings from a systematic literature review on the benefits and limitations of NEAT (the 4-h rule) commissioned by the Queensland Clinical Senate to inform future policy and targets. What are the implications for practitioners? There is evidence that a time-based target has been associated with a reduction in in-hospital mortality for emergency admissions to Australian hospitals. Concerns remain regarding a time-based target alone being used to drive redesign efforts at improving access to emergency care. A time-based target should be coupled with close monitoring of patient outcomes of emergency care. Target thresholds need to be evidence based and separate targets should be reported for admitted, discharged and all patients presenting to the ED. Journal compilation