difference between valid and reliable data

Calibrating an instrument involves measuring already known quantities too assess how accurately it is working. In order to be accurate in their work scientists need to first select a measuring instrument that allows an appropriate measure of accuracy eg a micrometer for the diameter of a piece of wire and a ruler marked in mm for its length and then to calibrate it. A micrometer measures length to a greater level of accuracy than a ruler which in turn measures length to a greater level of accuracy than a ‘clicker’ wheel. The level of accuracy of a measuring instrument determines the detail to which it can measure.An accurate measuring instrument, say a thermometer, is one whose readings confirm a known result.Is the ‘dropping a ruler’ experiment a valid measure of reaction time? AccuracyĪccuracy describes how well a measuring instrument determines the variable it is measuring. The points presented below, explains the fundamental differences between validity and reliability: The degree to which the scale gauges, what it is designed to gauge, is known as validity. Does seeing how far a ruler can drop through someone’s hand really measure reaction time? What other variables may be influencing the results? Validity describes whether the results of an experiment really do measure the concept being tested. Is the ‘dropping a ruler’ experiment a reliable measure of reaction time? Validity The Fremantle Back Awareness Questionnaire (FreBAQ) allows its assessment. Do this ten times and calculate the mean (average) result. IntroductionIn chronic low back pain (CLBP), disturbed body image has been highlighted as a contributor to the condition and a potential target for treatment. Note down the measurement where the ruler was caught. Try holding a ruler above a friend’s open hand and dropping it – they have to catch the ruler but may not move until they see the ruler start to move. Reliability is measured by a percentage – if you get exactly the same results every time then they are 100% reliable. When a scientist repeats an experiment with a different group of people or a different batch of the same chemicals and gets very similar results then those results are said to be reliable.

Being Reliable, Accurate & Valid Reliability

Difference between valid and reliable data