Tideiksaar 1993.

Methods	Randomised controlled trial. Method of randomisation not reported. No blinding. No losses to follow up reported. Intention‐to‐treat analysis.
Participants	Setting: one geriatric ward in the USA. N=70 Sample: 14% male. Age: mean (range) 84 (67‐97) years. Inclusion criteria: poor bed mobility (according to one or more abnormal factors on an observational 9 point performance‐orientated environmental mobility screen). Exclusion criteria: nil.
Interventions	Bed‐alarm system that produces an audible alert when the patient is about to exit or exits their bed. Control group received standard care.
Outcomes	1. Frequency of patient falls out of bed; 2. Frequency of all falls; 3. Frequency of patient injuries due to all falls; 4. Alarm response times; 5. Number of true alarms.
Notes	No significant difference in outcomes demonstrated.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information about the sequence generation process was available to permit judgement.
Allocation concealment (selection bias)	Unclear risk	Insufficient information about the sequence generation process was available to permit judgement.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No incomplete outcome data.
Selective reporting (reporting bias)	Unclear risk	The study protocol was not available.
Other bias	Low risk	The study appears to be free of other sources of bias.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not stated.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Outcomes were recorded by the study nurses who were not blind to intervention group.