Quality, Grade, Precision and Accuracy

We have discussed Quality in detail. There are some related concepts that you must know. These concepts will be helpful in two ways,

• firstly you will know them which is good from PMP exam point of view
• and secondly, studying these concepts will help develop the understanding of how they differ from quality

Quality

The degree to which a product meets its requirements

Grade

A category or rank used to distinguish items that have the same functional use but do not share the same requirements for quality

Example of Quality vs Grade

Suppose you need to buy a new phone for your Granny. Now who all remember the Nokia 1200? The feature phone that’s too dumb for today. Pretty limited in functionalities as compared to the current Android phones. Doesn’t have a camera or apps and can’t do much. But is pretty solid when it comes to making phone calls and long lasting battery. Now let’s compare that to an entry level Android phone that comes with a customized skin, bloatware and all other bells and whistles of today. Unfortunately the Android phone sometimes lags when multiple heavy applications run simultaneously, it may even crash.

These examples demonstrate that while the entry level Android phone is high grade i.e. it has lots of features and functions, it is low quality i.e. it doesn’t meet the criteria of “fit for use”.

On the other hand, the Nokia 1200 is lower grade but it is fit for use and Granny will be at peace with it. In other words, it is higher quality because it meets the needs, doesn’t break down and is useful.

Quality basically means something does what you need it to do. Grade has more to do with product’s value. Higher grade items will typically cost more than lower grade items but a higher grade item may not always do what you need it to do. Also, note that if Granny prefers handwritten letters, both Nokia 1200 and Android are low quality!

Quality and Grade aside, there is another distinction you need to know. It is the difference between accuracy and precision.

Accuracy

Accuracy is an assessment of correctness. Its basically how close a value is to its true value. An example would be how close an arrow gets to the bullseye center

Precision

Precision is an assessment of exactness. Its basically how repeatable a measurement is. An example would be how close a second arrow is to the first one (regardless of whether either is near the mark)

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