It is also important to note that the HLS-EU-Q47 is a subjective measurement and as such it does not include any objective items to measure functional health literacy.
It was therefore surprising to find relatively few studies measuring functional health literacy or components of interactive and critical health literacy (i.e. health knowledge, self-efficacy, patient motivation, confidence and social support) searched in this study.
This may influence the way in which our study compares to previous studies, the majority of which measured functional health literacy alone.
Given the fact that the SBSQ-D only measures functional Health literacy, the lack of correlation in our study is understandable since patient activation is a broader theoretical concept.
The All Aspects of Health Literacy Scale (AAHLS) is another recently developed tool, which aims to measure functional, communicative and critical health literacy.
The bar to achieving functional literacy is being raised all the time.
The OHLI is a validated functional literacy test, measuring not only reading comprehension but also numeracy ability [ 17].
Reading comprehension tests, such as the TOFHLiD, OHLI, OHL-AQ, HKOHLAT-P [ 17, 18, 25, 26] were constructed to evaluate functional literacy, and, therefore, measured a person's ability to understand and apply written information, including numerical data.
The most frequently used are the Test of Functional Health Literacy in Adults (TOFHLA) [ 5] and the Newest Vital Sign Test [ 6], which measure functional HL, or the Rapid Estimate of Adult Literacy in Medicine (REALM) [ 7], which assesses HL skills.
People with low functional literacy are less likely to achieve high health literacy however it is measured, not least because of the heavy reliance on written information across healthcare services.
