Table 5.

Frequency of phrases included in the PILs

Randomisation category	Summary of descriptions	Sample quote	PILs (n = 281) and video animation (n = 1)	Minimum acceptability score for category	Maximum acceptability score for category
1. Explanation of why randomisation is required in trials	To ensure that a fair comparison can be made between the groups and/or that bias is avoided	‘This is essential so that a fair comparison can be made between the two groups. Dividing people into treatment groups in this way is what is called a ‘randomised clinical trial’ and is the standard and most reliable way of comparing different treatment options’	91 (32.4%)	45.2	80.8
	To ensure the groups are the same at the start of the trial	‘to ensure that people in each group are equally matched’	29 (10.3%)
2. Synonyms for randomisation	Other words, e.g. you will be randomly assigned, you will be allocated at random, allocated by a process of randomisation	‘You will be randomly assigned to one of 2 groups’	65 (23.1%)	39.5	71.2
3. Comparative randomisation phrases	Comparing randomisation to the toss of a coin, or roll of a die, or lottery	‘…using a process which is similar to tossing a coin’	93 (33.1%)	24.7	69.8
4. Elaborative phrases further explaining randomisation	Explaining that there is an equal chance of being allocated to each of the groups in the trial, or that half of participants would receive one treatment and the other half would receive another	‘Your child will have the same chance of being put in either group’	167 (59.4%)	50.7	78.1
5. Phrases that describe the process of randomisation	Explaining randomisation was carried out by a computer, or centrally in a study office, or using sealed envelopes	‘…treatment given to each person in the study will be decided by a computer allocation. this will mean that neither you nor your doctors can decide which treatment you will receive’	135 (48%)	24.6	79.5
	Explaining that the participant/their doctor or any other person involved in the trial was not able to choose the participants treatment	‘neither you nor your doctors can decide which treatment you will receive’	89 (31.8%)
No explanation of randomisation			21 (7.5%)