Numbers, measurements, dates and time

[Tosin-Balogun]

Use this issue to discuss numbers, measurements, dates and time in the service manual.

We're particularly interested in hearing about user research findings.

If you want to comment on one of the topics on the page and there is a GitHub issue on that specific topic, please use that issue instead:

• calories - how to format them
• date format
• dates - Adding day of the week to date format
• Fahrenheit - removing values from content
• numbers - review how we use them
• numeral 1
• ordinals (1st, 2nd etc)
• [trimesters or weeks in pregnancy](https://github.com/nhsuk/nhsuk-service-manual-backlog/issues/209]

Related issues

• Ask users for their date of birth
• Date and time input
• Time - make "midnight" clearer
• Time format in patient information

[dom-marsala]

5.00pm or 5pm?

Doesn't mention specifics on https://service-manual.nhs.uk/content/numbers-measurements-dates-time

[sarawilcox]

I'm seeing quite a few professional users (policy makers, administrators and clinicians) for whom the use of numerals like 1 (rather than spelled out "one") is a distraction that cuts across their ability to read and understand the content. They keep wanting to correct it.

Update 25 Feb - user researcher fed back that virtually every user who tested our new tech guidance (professionals) was distracted by the number 1 and wanted to rewrite it as "one".

[sarawilcox]

Use of percentages/stats

There are some conversations going on around the use of percentages. The team working on contraception is looking at content on effectiveness of different methods. They've been using 1 in 100 women / 9 in 100 women, etc, as per service manual guidance.

But at yesterday's crit on the mini pill, colleagues were concerned this might be more confusing than using the official percentages that these 1 in 100 figures have been extrapolated from.

I’m struggling to find original research but it is well established practice in health literacy to avoid percentages. See this article by Canberra Health Literacy, for example: https://cbrhl.org.au/health-services-providers/communicating-with-consumers/communicating-risk-and-benefit/

Or something from the CDC on clear communication of probability: https://www.cdc.gov/ccindex/tool/page-20.html

There’s an FDA doc on Communicating risks and benefits: an evidence-based user’s guide which has a section on natural frequency vs percentages (p 56). It mentions that the results of studies have been equivocal.

But it includes an interesting study as follows. Peters et al “asked participants to imagine they had severe headaches and that a medicine existed that could decrease headache frequency. Participants read about a possible side effect of the drug in a percentage format (10% of patients get a blistering rash) or frequency format (10 patients out of 100 get a blistering rash). Less numerate participants perceived the medicine as less risky when side-effect information was presented using percentages rather than frequencies. Peters et al interpreted their results as being due to the frequency formats eliciting greater emotional imagery compared to percentage formats, which were relatively abstract and meaningless.” https://www.fda.gov/media/81597/downloadon

[sarawilcox]

Some comments on NHS.UK Slack:

Has anyone found/seen anything that isn't about communicating/understanding risk? I agree that for talking about side effects, complications etc., numbers are clearer. But when talking about how well something works (especially for the purposes of comparing options), I'm not sure if the same rationale applies - in the latter case it's not about interpreting what the stat means for you, but using it to understand if something is more or less effective than something else.

Percentages are used a lot in everyday life to talk about how well something works ("kills 99% of germs" is used over "only 1 in 100 germs survive") - so it's something people will likely be used to seeing.

It might potentially be easier to compare two options that are "95%" vs "99%" effective than it is to compare two products that don't work for "5 in 100 people" vs "1 in 100 people"?

My other fear is that "1 in 100" vs "5 in 100" makes it sound like the first option is 5 times better than than the second (whereas 99% and 95% would highlight actually they're much more comparable)

[sarawilcox]

One person overlooked the section on ranges of numbers. Is it easy enough to find? Is it in the right place?

[sarawilcox]

We should review our guidance on numbers in the light of GOV.UK research into users with dyscalculia.

[sarawilcox]

We're hoping to address the following issue at the June Style Council meeting: 5pm or 5.00pm. https://github.com/nhsuk/nhsuk-service-manual-community-backlog/issues/321#issuecomment-915039347

Also the question of how we format times - with a colon or full stop: https://github.com/nhsuk/nhsuk-service-manual-community-backlog/issues/167

[sarawilcox]

Graham P introduced this agenda item and explained how, at a Content Huddle last year, he invited a couple of speakers to talk about their work on low numeracy and dyscalculia.

Before the Style Council meeting, we shared some draft additional content for the page on Numbers, measurements, dates and time in the style guide.

The draft content is in this Word document on our internal SharePoint system: Style guide page on numbers, measurements, dates and time.docx

Action: we approved all the changes proposed in the Word document and will publish them, subject to clinical approval.

[sarawilcox]

In the BMI calculator tool on the NHS website, we allow users to choose to enter their weight in metric or imperial.

In the latest iteration of the calculator, where we give users advice about a recommended weight for their height, the Tools team is going to default to a result in the measurement that the user input.

[sarawilcox]

YOUGOV research into use of metric versus imperial

72% ... describe their weight in stone and pounds far outweighing the 24% who describe it in kilograms.

However, break the results down by age and we can see a significant shift occurring at the younger end of the spectrum. The youngest Britons surveyed (18-29 year olds) are almost evenly split, with 47% still using imperial but 44% using metric.

This appears to be a very recent trend, with the next age group up – 30-39 year olds – coming heavily down on the imperial side (66% vs 31%). But with the direction of travel across every measure clearly towards greater adoption of metric by younger generations, we can probably expect to see more and more people describing their weight in kilograms as time goes by.

There is also one measure that we asked about where metric is firmly assimilated: temperature. Almost three quarters of Britons (72%) say they use Centigrade to describe how hot it is, compared to only one in five (19%) who say Fahrenheit. Even among the oldest Britons – those aged 70 and above – metric leads by 54% to 36%.

[steph-w-nhs]

In the BMI calculator tool on the NHS website, we allow users to choose to enter their weight in metric or imperial.

In the latest iteration of the calculator, where we give users advice about a recommended weight for their height, the Tools team is going to default to a result in the measurement that the user input.

More info on our logic behind showing users a 'best weight range for their height'.

• The current BMI tool shows users this weight range in the measurement they've selected, e.g. (41.6kg - 56.3kg or 6st 10lb - 9st 1lb)
• Our redesigned tool will only show users the weight measurement they’ve entered. This means we are not showing the opposite measurement in brackets as this is not considered 'useful information' in the context of when someone has already chosen their preferred measurement
• We will spell out measurement in full (kilograms/stone/pounds). Screen reader reads the abbreviations wrong (lbs as L B S). Some accessibility experts recommend not changing content especially for screen readers, as assistive tech users are usually familiar with the quirks of their software. But people who do not have English as their first language may not know what st and lbs are.
• Include the measurement after each instance of a number (41.6 kilograms and 56.3 kilograms) to keep it consistent with ‘stone/pounds’ pattern (e.g. 6 stone 10 pounds and 9 stone 1 pounds)
• Always include decimal places in kilograms the range for a kilogram is quite large and users may track the decimal place when weighing themselves
• If the imperial measurement has no ‘pounds’ value, we do not include the blank value. E.g ‘6 stone and 0 pounds’. We'll just show '6 stone'

[sarawilcox]

Time - from Health literacy toolkit

The numeracy levels below are defined in the Government 2011 Skills for Life Survey. This estimates that: • 24 in 100 adults in the UK (25%) are below entry level 2 – almost a quarter • 49 in 100 adults in the UK (49%) are at or below entry level 3 – that’s nearly a half of all adults

That of a typical 7–9-year-old(Numeracy entry level 2) • Able to understand appointment times in whole hours using 12-hour clock e.g. 9am, but not parts of an hour or a 24 hour clock e.g. 9.15am or 13.00 hour

That of a typical 9–11-year-old (Numeracy entry level 3) • Able to understand appointment times using 12-hour clock e.g. 9.15 but not 24 hour clock e.g 14.15

[SMorgan-Leith]

As part of the redesign of the child BMI calculator, we decided to display the result of "0" (centile) as "below 1". We were aware that 0 is a frightening result for parents and that this should be handled with sensitivity. A child may get an underweight result but still be healthy, so we wanted to focus on the 'What the result means' part of the page, so that parents and carers can best understand their child's result. In user testing, none of the users questioned this result. Overall feedback was that the results presented "weren't scary" which users liked.