An analyst from the Pension and Population Research Institute gave a rapid-fire talk. This was a five-minute talk at the Royal Statistical Society conference in Manchester. That talk (plus a poster) asserted a strong link between abortions and breast cancer. **Note: **this article will discuss abortion and breast cancer statistics in the United Kingdom.

There are many statistical problems with this poster.

**First, correlation is not causation.** The main assertion is abortions and hormonal contraceptives cause breast cancer. The provided evidence for this assertion are associations among age cohorts:

**To reiterate: correlation is not causation. **Imagine there were researchers at…

**When analysing data, what decisions do we make? **Given a problem to solve, there are many dividing paths we could take. Those decisions could affect outputs of our analysis, such as estimates and intervals.

A pre-print analysis gave the same data and question to 73 research teams. The data involved six questions from multi-country International Survey Programme. The teams also had measures of the stock and flow of immigrants to each country. The hypothesis was whether immigration reduces support for social policies among the public.

These 162 researchers then had to catalogue their decisions, submitting 1,261 models. Also, there were…

In children, a SARS-CoV-2 infection often has no symptoms or induces only mild disease. Fatalities among children are rare, but mortality is not the only concern. Some people with Covid-19 may experience symptoms long after recovering from infection.

**How many children have ‘long COVID’? **For the United Kingdom, there are two sources on the prevalence of post-COVID syndrome.

The Office for National Statistics conducts a random infection survey. **The survey is of private households.** It does not include hospitals, care homes, or other institutions like prisons. As part of that survey, respondents answer this question:

Would you describe yourself as…

Prof Michie (UCL) asks:

Information is absolutely key. We need more data, not less data. Everybody should be able to know, for example, what is the prevalence of Covid in the neighbourhood?

**These statistics exist, so this article looks at what people can see.**

On the Public Health England dashboard, you can type in your postcode.

Using an example postcode (from Central North, Swindon), we get:

- The number of people testing positive, by swab date, in a seven-day period. For the seven days to 20th August, that is 45.
- The number per 100,000 people, based on a population estimate…

In our recent co-written column with Sir David Spiegelhalter, we wrote:

if we just look at women who are currently or recently pregnant, this rises to 37%; far higher than the 13% of live births by mothers of black or Asian ethnicity.

That part should read:

if we just look at women who are currently or recently pregnant, this rises to 34%; far higher than the 17% of live births classified as Black or Asian ethnicity.

**All apologies.**

The Intensive Care National Audit and Research Centre (ICNARC) produces weekly reports. These publications cover around 40,000 patients in critical care. …

FoodHub, a takeaway delivery service, claim cheese slices are Britain’s favourite cheese. Different outlets laundered the assertion: including Indy100, Mail Online, and the Metro.

Their press release only says it is a “nationwide poll by us”. Yet, the FoodHub post contains no information about survey methods.

It fails to describe the sample size, target population, or sampling procedure. Some articles state the survey was of 2,000 Brits, but the press release does not say this. Neither does it detail the question wording, order, or response options. The fieldwork period and weights are unknown. There are no data tables.

**To reiterate…**

A journalist from the *Financial Times* spoke to me about vaccination statistics. I used an analogy to help explain why the vaccinated share of deaths rises as coverage grows:

About two-thirds of people who die on UK roads are wearing a seatbelt, but this is a consequence of usage rates of nearly 99 per cent, Masters said. He added that the same logic applied to severe disease and death in highly vaccinated populations.

**These figures are imprecise. **What I recall saying was:

In Great Britain, most car occupants who die in incidents are wearing seat-belts. …

Back in 2019, the President of the American Statistical Association (ASA) launched a task-force into p-values. This task-force started after an editorial in *The American Statistician, *an ASA journal. People may have mistaken that editorial for official ASA policy.

An informal definition of a p-value is:

the probability under a specified statistical model that a statistical summary of the data would be equal to or more extreme than its observed value.

The task-force’s statement says:

Much of the controversy surrounding statistical significance can be dispelled through a better appreciation of uncertainty, variability, multiplicity, and replicability.

Often, journal articles will use…

**The p-value is a misunderstood statistic. **Sometimes, textbooks carry incorrect definitions — perpetuating misinterpretations.

For example, a Twitter user shared a 2003 biology textbook definition:

The P-value is the bottom line of most statistical tests. It is simply the probability that the hypothesis being tested is true. So if a P-value is given as 0.06, that indicates that the hypothesis has a 6% chance of being true.

**This is wrong.**

A better definition of the p-value is, from the American Statistical Association:

the probability under a specified statistical model that a statistical summary of the data would be equal to…

How many potential years of life do people dying of Covid-19 lose? That is a prominent question in the pandemic. It is another way of showing mortal impacts, giving greater weight to younger deaths.

**What does ‘years of potential life lost’ mean? There are different definitions. **One definition compares a person’s actual age at death with life expectancy at that age. The difference is then the potential years of life lost. It is a difference between reality and expectation. Such analyses could also account for co-morbidities.

Another definition compares actual death ages with a reference age. If a person dies…