Positive and False Negative: Part I
This topic is
really rather important, since we make all sorts of decisions
based on what we observe, on research findings, on test results,
and so on. If we don't know about these two possible
results of our observations, etc., we can make decisions without
considering the full implications.
So in case you don't
know what these are, here's another
story to help explain, one that highlights how important it is
to know about False Positives and False Negatives.
happen, even when we try our best
dealing with reality again. Robert and Harold went through
some medical testing in order to find out if there was some sort
of illness causing their symptoms. Now, the results each received could
have been true (they could have shown reality), or false (they
could have failed to show reality).
And as it happened,
for this example, the test
results were actually wrong (false) for both men. They did not
provide valid conclusions about the real health of either.
And that's what can happen whenever we try to know reality.
We can make a mistake. We do all we can to prevent that,
but it can happen.
were a false positive. They said he had leukemia, when he didn't
That's what a false positive is, saying something is true (the
test said Robert truly had leukemia) when it is not true (he
didn't really have leukemia).
were a false negative. They said he didn't have leukemia when he did.
That's what a false negative is, saying something is NOT true
(the test said Harold truly did not have leukemia), when it is
not false (he really did have leukemia).
through unnecessary and arduous treatment, while Harold failed to receive
treatment he needed.
lived. Harold died.
ask: Who would
you rather be, Robert, or Harold?
everyone would prefer is to be neither. We would wish to avoid
both false positives and false negatives. We would want
true positives, or true negatives. Unfortunately,
that's not always possible.
So, since there can always be
some errors in medical test results, which would you prefer,
being told you were sick, when you're really not, or being told
your not sick, when you really are? If these were the
only two choices, would you prefer to go
thorough unnecessary and grueling treatment and live, or receive
no treatment and die?
In other words, which
error would you be most willing to make, a False Positive, or a
Well, for the most part it depends on context...
contexts we're more willing to make a False Positive, while in
others we're more willing to make a False Negative. For
Medicine: When it
comes to medical results, especially when a possible fatal
illness is involved, most would prefer a possible error to
be a false positive (saying we have an illness when we
don't) rather than a false negative (saying we don't have an
illness when we do). Generally, we're not keen on dying
from a failure to diagnose a fatal illness.
Interestingly, when it comes to someone being tried for murder,
we tend to prefer to let a guilty person go free (a false
negative--finding a guilty person not guilty) to a false
positive (finding an innocent person guilty), since in many
states we execute people convicted of murderer. Generally, we're not keen on
executing innocent people. Or at least that used to be our
you'd like to know more about false positives and false
read about intelligence
read about reasoning and how we can use it
read about Critical Thinking and how it benefits us
read about a couple ways of thinking (divergent and convergent)
read about causality
read about who likes it when people are ignorant, or stupid
go the Articles Page.