Evidence Quality
What does ‘good quality’ mean? Meaning: Something of high standard/has more value. Ex: designer bags, luxury cars
Sample Size Meaning: Choosing part of a population to study, not the whole population.
Why is sample size important? Larger sample sizes allow scientists to better determine the average values of their data, and they can avoid errors from testing a small number of people who might not represent the whole population.
What is good quality evidence? Source of information - Where does the information come from? Dr. Grossman from Rutgers University Scientist from Robert Wood Johnson FDA, CDC (Government agencies) Sample size - number of people 10 people - 500 people (More people the better!) Details - What method was used to conduct the experiment? Questionnaire, procedure explained , uses many details
Evidence rating 0 -terrible 1- poor/bad 2- okay 3- good
Example 1 Scientist conducted a study with 1000 people who all have stomach ulcers. They tested the effectiveness of the following medicines on reducing stomach ulcers: Prevacid and Zantac. Scientist gave 500 people with ulcers Prevacid and gave another 500 people with ulcers Zantac. This is what scientist found: Scientist concluded that Zantac was more effective at reducing stomach ulcers. # of people without stomach ulcers after 1 week # of people without stomach ulcers after 2 weeks Zantac 329 448 Prevacid 345 402
How would you rate this evidence? It is a 3 or good. Why? Conducted by scientist/doctor/or expert. Used a large sample size (1000 people) The method and a chart was used to explain the results with many details.
Example 2 Ms. Monica has 3 children. Recently, all three of her child develop symptoms from a stomach ulcer. She believes that her children got ulcers from school. She says that other kids in their classes have poor hygiene so through cross- contamination the disease spreads to each child. The only way to cure this is with hot water and lemon.
How would you rate this evidence? This evidence is a 0 “zero” or terrible. Why? Ms. Monica is a random person (not a scientist, doctor) This is just what she thinks and she has no experience Other children may have different illnesses
Example 3 Greener Pharmaceutical company conducted a test on new allergy medicine with 20 people, who usually suffer from allergies. They gave 10 people the new medicine, while the other 10 people got no medicine. They monitored their symptoms for a month. They concluded that the 10 people who took the medication got much better but the 10 people who did not showed no improvement.
How would you rate this evidence? This evidence is a 1 or 2, it is okay. Why? The study is done by a scientific company The study uses the scientific method But, they have a small sample size and more participants would be better.
Example 4 Doctor Steven’s examined one of his patients who had a sore on his leg and tested it for a certain type of bacteria. He found that this patient had the bacteria in his sore. He saw another patient two days later who also had a sore. He decided this patient had the same bacteria.
How would you rate this evidence? This evidence is terrible a 0 or “zero” . Why? The study is done by a doctor But, he is only looking at one (1) patient, and other patients could have a different bacteria or none at all. A study or questionnaire with only 1 person is never good.
What is good evidence used for? You use good evidence & details to support your claim (model) Also to convince others that you used the proper procedures and scientific methods so your explanation or model is good quality.