General Engineering Introduction/Data
Do not collect data unless there is a rational reason to do so. The reasons fall into two categories:
- isolating problems
The biggest problem with data is that it must be presented and analyzed well. Engineers will not quibble about English. They will forgive all sorts of strange behavior. Numbers wake them up. All of a sudden they start paying attention. Then they start asking questions that can cement or ruin your engineering reputation.
For instance, suppose you've designed a mechanism to clean algae off the glass of an aquarium tank that doesn't involve sticking your hands in the water. You want to quantify how clear the glass is. So you measure light intensity from the aquarium hood light before and after the cleaning. More light means a cleaner aquarium.
Here are the typical mistakes:
- no baseline .. How clean is a traditionally cleaned tank? How clean is the average tank?
- no possibility of failure .. What does a very dirty tank look like in the data?
- not enough data .. statistics demands a certain number of samples. One test may not be enough.
- fascination with outliers
- bad statistics, randomly fitting lines with no hypothesis
- after the fact logic Crabtree's Bludgeon
- expectation blindness
- narrative not obvious from the data
It is important to have the data in a spreadsheet and at one's finger tips to look at in detail. Trust the raw data. Display it during a presentation. Make only the analysis that you are 100 percent confident of. In future classes you will be taught more about data and how to analyze it. Know your limits. Give the audience a chance to educate you. Learn from the audience in the moment.
Realize that many engineers are more comfortable with numbers than words. They will relax, give advice and be nice ... in their minds. You may feel criticized. They may make you feel like a failure. Have courage. Forgive them. Display the data with silence ... don't talk. See what they do. Agree with them and keep the conversation going. Climb into their minds. Entertain them and you will grow comfortable in a completely different world where numbers don't lie.