Issues that are perennial or long-standing such as opinions on abortion or capital punishment generally do not change quickly. However, issues that the public knows little about, such the situation in Haiti, or in Bosnia, often show significant changes in public opinion in short periods of time. This is also true of approval ratings. They can change rapidly. Another common error is to state exact numbers when it is clearly impossible to know if the numbers are exact.
Nobody knows exactly how many people live in the United States today.
If someone says that there are 265 million people in the USA, he almost has to be wrong. If a Senator says that his bill will reduce spending on Medicaid by ten billion dollars over the next five years, he is saying something he cannot possibly know. It will not be exactly ten billion dollars, and it may well be considerably more or less. No one knows how many people will apply for and be accepted for Medicaid payments over the next five years. Critical thinking involves checking the source of statistics or numbers.