what really happens?
"There are lies, damned lies, and statistics."
Often, we observe that data are misused to lie to us about various subjects. Statistics may be unreliable when they are used to bolster a political or social agenda, and presented without adequate explanation as to their provenance. It is easy to generalize all statistics in this way, even those that are documented properly, and created by methods that are widely accepted by the scientific community. When we as readers don't know where data comes from, who gathers it, what they gather it for, or what is being left out, we suspect it - sometimes rightly so. We then must be persuaded by other means.
"One swallow does not a summer make."
The well-documented phenomenon known as "confirmation bias" refers to the human tendency to seek out evidence that supports our claims, and avoid evidence that would disconfirm them.
As an example, let's take the observation that some streetlamps go out as people walk by. If first one, and then another streetlamp went out as I walked under them at night, it might occur to me that my presence interfered with the proper operation of streetlamps. I would begin to focus on and remember very well all the lights that went out as I walked by, and might begin telling my friends about my new powers. Things I might not do include counting the number of lights that stayed lit, or testing my theory by walking in a different neighbourhood or city, or researching how streetlamps work. Though they would lead me faster to the truth, I wouldn't think of doing these things, because they would undermine my theory.
If I were particularly passionate about my streetlamp-powers theory, I might begin to question or even disregard evidence to the contrary. If my friends responded to my claim with a mundane explanation (for instance, that streetlamps go out regularly when their bulbs are nearing the end of their lives), I might argue that they are lying because they are biased against my possessing streetlamp powers, and then stop listening to what they have to say.
"The plural of anecdote is not data".
For precisely this reason, a collection of stories cannot be considered valid evidence. As humans, we tell and remember stories that confirm our beliefs, and usually forget to tell stories with which our beliefs clash. With vanishingly rare exceptions, anecdotes should never be accepted as valid evidence of a broad claim.
This is why it troubles many people to hear the kind of evidence that has been presented in the current American debate over who should pay for healthcare.
People in countries whose governments provide universal healthcare coverage generally have longer life expectancies, lower infant mortality rates, and average medical costs less than half as expensive as Americans'. By contrast, in the United States, where healthcare is paid for by private insurers, average life expectancy is 50th highest in the world, infant mortality is only 44th lowest, and medical goods and services are more expensive than anywhere else on the planet. But these, after all, are only statistics.
These facts are insufficiently compelling to people who are opposed to the idea of universal healthcare coverage. Few American politicians dare even speak them aloud. Far more compelling are those anecdotes - whether true or false - in which universal healthcare failed (and it is worth noting that such anecdotes are rarely accompanied by stories of private insurance's success). In the current debate, people who are opposed to universal healthcare coverage repeat these stories to the near-exclusion of any other facts, which has led to a frankly appalling state of discourse.
They don't realize the other reason that anecdotes aren't data: One good story and one bad story cancel each other out.
For every Shona Holmes, there are thousands of people who received successful treatment, but their stories aren't being told. For a variety of reasons, the state of medical care in America and other countries is being grossly misrepresented by individuals with political agendas, and accordingly little concern for the truth. The collection of stories on this website is not intended to be taken as valid evidence of any position, but to provide a more comprehensive picture of just what really happens.
It isn't sufficient, but it has become necessary.