Measurement of these factors is in keeping with previous research that has assessed CRC screening knowledge [52] and the UK General Medical Council guidelines GSK J4 mw for consent [15]. The phrasing and response options mirrored the gist-based style of the leaflet [53] and [54]. We calculated the total number of individuals who answered each statement correctly (statement totals) as well as the mean number of statements correctly answered per participant (individual

totals). Data from the semi-structured interviews were digitally recorded, transcribed verbatim, and analysed using thematic analysis, which is a qualitative technique for identifying patterns (themes) within data [55]. The purpose of the thematic analysis was to pin-point the particular areas of the gist-based leaflet that caused difficulties with comprehension. The majority of participants were female (75%), employed (54%), white (54%), had a GCSE level of education or below (57%), adequately literate (82%), without a partner (68%), ICG-001 spoke English as a first language (75%), and had either received a cancer diagnosis themselves (11%) or knew someone that had (82%). The majority had used written documents in their current of previous employment at least some of the time (75%) (see Table 1). As rounds progressed, more individuals had a lower level of education,

marginal or inadequate health literacy scores, spoke English as a second language, or were from a minority ethnic group. As demonstrated in Table 2, the majority of the Palmatine statements were answered correctly by at least 80% of participants. However, two statements (‘The FOB test is done at home’ [T] and ‘People with an abnormal result always have cancer’ [F]), were answered correctly by less than 80% of participants. At an individual level, participants were able to answer a mean of 7.2 out of

8 statements correctly (range = 5–8). In response to the threshold not being met for the statement that ‘the FOB test is done at home’, we changed the word ‘post’ to ‘home’ in the following sentence to clarify where the test was completed: ‘A FOB test kit with instructions is sent through to the home’. More than 20% of individuals did not correctly answer the statement that an abnormal test result does not necessarily mean cancer has been found. One participant commented that: ‘I do wonder about the fact that if you have an abnormal test that it doesn’t necessarily indicate that you’ve got cancer. That’s inferred but it doesn’t necessarily say that’ (AL, 55 years, female, degree level education). To improve comprehension of the meaning of an abnormal result, we added the following sentence: ‘An abnormal result does not always mean cancer has been found’.