IMARCS staff course · Module 1
How to Think
How to work through any problem: observe before you conclude, tell symptoms from causes, check the facts, rule causes out, change one thing at a time, put first things first, and check your fix worked.
- 1. Why thinking beats memorizing
- 2. Observe before you conclude
- 3. A symptom isn't a cause
- 4. Check the facts before you act
- 5. List the causes, then rule them out
- 6. What changed?
- 7. Together isn't the same as cause
- 8. Change one thing at a time
- 9. Put first things first
- 10. Act, then check that it worked
- 11. Judging claims and advice
- 12. Know your limits, and report clearly
Key terms for this module
Read these first. Every one of them comes up in the sections below.
| Observation | Something you can see, hear, smell or measure. A fact. |
| Conclusion | What you think an observation means. A guess until it's checked. |
| Symptom | What you notice when something is wrong. |
| Cause | Why it's happening. |
| Process of elimination | Listing every possible cause and ruling them out with evidence until one is left. |
| Correlation | Two things changing together. Not proof that one causes the other. |
| Triage | Deciding what to deal with first: safety, then stopping damage, then the cause, then clean-up. |
| Anecdote | One person's story. Not the same as evidence. |
| Evidence | Something you saw, measured or tested that supports or rules out a cause. |
1. Why thinking beats memorizing
Rules and checklists are useful, but nobody can write a rule for every situation. Sooner or later you'll face something nobody planned for. When that happens, what saves the day is a person who can think it through.
This module isn't about aquariums. It's about how to think through any problem: a car that won't start, a phone that won't charge, a leak under the sink. Every later module uses the same method, so learn it here with everyday examples first.
The method is a loop. Observe what's really happening. Check the facts before you believe them. List every cause it could be. Rule causes out with evidence. Act, starting with the safest useful step. Then check whether it worked. If it didn't, go round again with what you've learned.
The goal isn't to remember the answer. It's to be able to work out the answer when nobody has told you.
| If | Then |
|---|---|
| Something happens that no rule covers | Use the loop: observe, check, list, rule out, act, check. |
| Your fix doesn't work | Go back round the loop. You've learned something. |
Check your understanding
Your workplace has a checklist for when the power goes out. Today the power is on, but one room has no lights and the others are fine. The checklist doesn't cover this. What do you do?
Use the loop. Observe: only one room, lights only, or sockets too? Check: is the switch on, are the bulbs fine? List causes: bulb, switch, a tripped breaker for that room. Rule them out one by one. Then act, and check.
Key point Observe, check the facts, list causes, rule them out, act, check.
2. Observe before you conclude
Most mistakes start in the first few seconds: someone sees something, jumps to a conclusion, and acts on the conclusion instead of what they saw.
- 1. Observe
- 2. Check the facts
- 3. List causes
- 4. Rule them out
- 5. Act
- 6. Check
An observation is what you can see, hear, smell or measure: "there's water on the floor next to the dishwasher." A conclusion is what you think it means: "the dishwasher is leaking." Conclusions feel like facts, but they're guesses until you check them.
Good observers look at the whole picture, not just the first thing that catches their eye. Where exactly is the water? How much? Is it clean or dirty? Is it still coming? When did it start? Each detail rules some causes in and others out.
Attention to detail is a skill, not a personality type. It means reading the whole label, noticing the unit (grams or kilograms?), and noticing what's different from yesterday. Small details are often the whole answer.
| If | Then |
|---|---|
| You see something and immediately know "what it is" | That's a guess. Write down what you actually see first. |
| You only look at the first thing you notice | You miss the details that point to the cause. |
| You skip the unit on a label | Grams and kilograms are a thousand times apart. |
Check your understanding
A coworker says, "The fridge is broken, the milk went bad." What would you want to observe before you agree?
Is the fridge cold inside? Is it running? Is the door closing properly? What's the date on the milk? "The milk went bad" is an observation. "The fridge is broken" is a guess.
Key point Facts first. Guesses are guesses until they're checked.
3. A symptom isn't a cause
A symptom is what you notice. A cause is why it's happening. Fixing a symptom makes the problem look better for a while. Fixing the cause makes it go away.
- 1. Observe
- 2. Check the facts
- 3. List causes
- 4. Rule them out
- 5. Act
- 6. Check
Mopping the floor fixes the symptom. If the cause is a dripping pipe, the water is back tomorrow. Taking a painkiller for a toothache helps today, but the tooth still needs a dentist. Covering a warning light on a car dashboard doesn't fix the engine.
One symptom can have many causes, and one cause can make many symptoms. So whenever you fix a symptom, ask: what caused this, and is it still happening?
Sometimes you have to treat the symptom first because it's dangerous right now: you mop up water near a power socket before you go looking for the leak. That's fine. Just don't stop there.
| If | Then |
|---|---|
| You fix the symptom | It looks better for now. It comes back if the cause is still there. |
| The symptom is dangerous right now | Deal with it first, then go find the cause. |
Check your understanding
Every morning there's a small puddle under the car. Someone puts a tray under it. Has the problem been solved?
No. The tray catches the symptom. Something is still leaking, and the cause (and what's leaking) still needs finding.
Key point Always ask: what caused this, and is it still happening?
4. Check the facts before you act
Before you act on a number, a report or a warning, make sure it's true. Tools give wrong readings, people misremember, and messages get passed on wrong.
- 1. Observe
- 2. Check the facts
- 3. List causes
- 4. Rule them out
- 5. Act
- 6. Check
Ask three questions about any fact you're about to act on. Where did it come from? (Did you see it, or did someone tell you?) Could the tool or the person be wrong? (Was the thermometer just in hot tea? Was the scale set to zero?) Does it fit everything else you can see? (A "fever" in a child who's running around happily doesn't fit.)
If a fact doesn't fit, check it again before you do anything. A careful second look costs a minute. Acting on a wrong fact can cost much more.
| If | Then |
|---|---|
| A reading doesn't fit what you can see | Check the reading, the tool and how it was used. |
| Someone passes on a message | Find out if they saw it, or heard it from someone else. |
| You act on one strange number | You may "fix" something that wasn't broken. |
Check your understanding
The bathroom scale says you gained 6 kg overnight. What do you check before you believe it?
Is the scale on a flat, hard floor? Was it zeroed? Does it read the same twice? Does a known weight read right? A change that big overnight almost certainly isn't real.
Key point Check the number before you act on it.
5. List the causes, then rule them out
Don't bet on the first idea that comes to mind. List everything that could cause what you're seeing, then test the list until only one cause is left.
- 1. Observe
- 2. Check the facts
- 3. List causes
- 4. Rule them out
- 5. Act
- 6. Check
This is called process of elimination. A phone won't charge. It could be the socket, the charger block, the cable or the phone. Test each one on its own: plug a lamp into the socket, try the charger with another phone, try a different cable. The part that fails its own test is the cause.
Order your checks sensibly. Check the most dangerous causes first (a burning smell from the charger comes before anything else), then the most likely ones, then the quickest and cheapest to check. Cross each one off only when you have evidence, not because it "probably isn't that".
Keep track of what you've ruled out and how. Write it down. The next person, or you tomorrow, shouldn't have to check it all again.
| If | Then |
|---|---|
| You bet on the first idea | You may chase the wrong cause for hours. |
| You cross off a cause because it "probably isn't that" | It might be. Rule it out with evidence. |
| You test each part on its own | The one that fails its own test is the cause. |
Check your understanding
A desk lamp won't turn on. List the causes, and how you'd rule each one out.
The socket (plug something else in), the plug or fuse, the cable (look for damage), the switch, the bulb (try a bulb that works). Check anything that smells of burning first, then the quickest: the bulb and the socket.
Key point Dangerous first, then likely, then quick and cheap. Evidence, not hunches.
6. What changed?
Things that have worked for months don't usually break for no reason. When a problem starts, the most useful question is: what changed just before it started?
- 1. Observe
- 2. Check the facts
- 3. List causes
- 4. Rule them out
- 5. Act
- 6. Check
A new cleaning product, a different brand of food, a moved piece of furniture, a new person doing a job, a power cut, a hot day. Any change just before a problem is a suspect. Look back a day, a week, sometimes longer, and list every change you can find.
A change is a suspect, not a conviction. The cat may have caught a cold that happens to line up with the new spray. Test it: stop using the spray. If the sneezing stops, and comes back if the spray comes back, you've found your cause.
| If | Then |
|---|---|
| A problem starts suddenly | Look for what changed just before it. |
| You find a change | It's a suspect. Test it before you blame it. |
Check your understanding
A houseplant that's been healthy for a year starts dropping leaves this week. What's the first question you ask?
What changed? Was it moved? A new window open? Heating switched on? A different person watering it? Then test the most likely change.
Key point First question: what changed?
7. Together isn't the same as cause
Two things happening together doesn't prove one causes the other. This is one of the most common thinking mistakes there is.
- 1. Observe
- 2. Check the facts
- 3. List causes
- 4. Rule them out
- 5. Act
- 6. Check
When two things rise and fall together, there are several possibilities. A causes B. B causes A. Something else causes both. Or it's coincidence. Ice cream sales and sunburns rise together because hot sunny weather causes both, not because ice cream burns your skin.
Before you decide one thing caused another, ask: could something else explain both? And can you test it? If removing the suspected cause removes the effect, and bringing it back brings the effect back, you have much stronger evidence.
| If | Then |
|---|---|
| Two things happen together | One may cause the other, or something else may cause both. |
| Removing a suspected cause removes the effect | That's much stronger evidence. |
Check your understanding
Every time Tanaka-san is on shift, the printer jams more. Is Tanaka-san causing the jams?
Maybe, but not proven. Maybe Tanaka-san's shift is the busiest, or the same day the paper delivery comes. Look at what else is different on those shifts, and test it.
Key point Ask: could something else explain both?
8. Change one thing at a time
If you change three things and the problem goes away, you don't know which one fixed it. If it gets worse, you don't know which one broke it.
- 1. Observe
- 2. Check the facts
- 3. List causes
- 4. Rule them out
- 5. Act
- 6. Check
When something isn't working and there's no emergency, change one thing, wait long enough to see the effect, and check. Then decide the next step. It feels slower, but it's faster in the end, because you learn something from every step.
Overreacting is the other half of this. Someone turns the shower to hot, doesn't wait, turns it far to cold, doesn't wait, and swings back and forth. Every system takes time to respond. Make a small change, wait, check, then adjust. Doing too much, too often, or doing things that cancel each other out usually makes problems worse.
The exception is an emergency. If something is dangerous right now, do what makes it safe, even if that means doing several things at once. Then go back to one change at a time.
| If | Then |
|---|---|
| You change three things at once | You can't tell which one helped or hurt. |
| You make big changes without waiting | You overshoot, back and forth, like the shower. |
| It's an emergency | Make it safe first, even if that takes several actions. |
Check your understanding
A soup tastes bland. Someone adds salt, pepper, lemon and soy sauce at once. Now it's too sour. What went wrong, and what should they have done?
They changed four things at once and can't tell which made it sour. Add one thing a little at a time, taste, then decide the next.
Key point Small change, wait, check, then decide.
9. Put first things first
When several things are wrong at once, the order you deal with them matters. Safety first, then stop the damage, then fix the cause, then clean up.
- 1. Observe
- 2. Check the facts
- 3. List causes
- 4. Rule them out
- 5. Act
- 6. Check
This is called triage. A pipe bursts under the sink and water is spreading toward a power strip. First make it safe: switch off the power at the wall if you can do it safely. Then stop the damage: turn off the water. Then find the cause. The mopping comes last.
When you're not sure what to do first, ask: what happens if I leave this for ten minutes? Anything that gets dangerous or much worse in ten minutes comes first.
| If | Then |
|---|---|
| Water is spreading toward electricity | Safety first: make the electricity safe. |
| Damage is still happening | Stop it before you fix or clean. |
| You're not sure what's urgent | Ask what happens if you leave it ten minutes. |
Check your understanding
You walk into a room. A heater is smoking, the floor is wet, and a coworker's cut their hand on broken glass. What order do you deal with these in?
Safety first: switch off the heater at the wall if you safely can, and make sure your coworker is OK and away from the glass and water. Then stop more damage. Then causes. Clean-up last.
Key point Safety, stop the damage, fix the cause, clean up.
10. Act, then check that it worked
Doing something isn't the same as fixing something. Every action needs a check: did it actually work?
- 1. Observe
- 2. Check the facts
- 3. List causes
- 4. Rule them out
- 5. Act
- 6. Check
Before you act, decide two things. What will tell me it worked? (The floor stays dry. The phone shows it's charging.) When will I check? (In an hour. Tomorrow morning.) Then actually check, at that time.
If it worked, write down what the problem was, what caused it, and what fixed it. If it didn't, that's useful too: you've ruled something out. Go back round the loop with that new fact.
Some fixes come with their own risks. Pick the step that helps without being able to make things worse, when there's one. Turning off a dripping tap can't hurt. Taking apart the plumbing could.
| If | Then |
|---|---|
| You act without deciding how to check | You won't know if it worked. |
| It didn't work | You've ruled something out. Go round again. |
Check your understanding
You tighten a dripping tap. How do you know it's fixed?
Decide in advance: a dry sink after an hour, checked at a set time. Then actually check. If it's still dripping, the washer may be the cause, not how tight it was.
Key point Decide what "fixed" looks like and when you'll check. Then check.
11. Judging claims and advice
You'll hear a lot of advice: from coworkers, the internet, product labels and people who "always do it this way". Some of it's right. Some of it isn't. You need a way to tell the difference.
- 1. Observe
- 2. Check the facts
- 3. List causes
- 4. Rule them out
- 5. Act
- 6. Check
| Ask | Why it matters |
|---|---|
| Who's saying it, and how do they know? | Did they test it, or did they hear it from someone else? |
| Is it one story, or many results? | One person's good experience is an anecdote. It may have been luck or something else entirely. |
| Are they selling something? | A product label wants you to buy the product. That doesn't make it wrong, but check it. |
| Does it fit what you already know works? | A claim that breaks everything you've learned needs much stronger evidence. |
| Can you test it safely and small? | Try a change on a small scale first, and check the result. |
"We've always done it this way" isn't a reason. It may be a good way, but you should know why it's done that way. If nobody knows why, find out.
| If | Then |
|---|---|
| Someone says "it worked for me" | That's one story. It might have been something else. |
| The claim is on a product label | The seller wants a sale. Check it. |
| "We've always done it this way" | Find out why. |
Check your understanding
A coworker says a new cleaning product "kills everything and is totally safe". How would you judge that?
Who says so and how do they know? Is it the label (a seller), or a test? What does the safety sheet say? Try it small first, and check what happens.
Key point Ask how they know, and test small.
12. Know your limits, and report clearly
Thinking for yourself doesn't mean doing everything alone. A good problem solver knows when something is beyond them, and hands it over with everything the next person needs.
- 1. Observe
- 2. Check the facts
- 3. List causes
- 4. Rule them out
- 5. Act
- 6. Check
Get help when the problem is dangerous and you don't know how to make it safe, when you've run out of causes to check, or when the next step could cause serious damage if you're wrong. Asking early is better than guessing late.
When you report a problem, say: what you saw (facts, with numbers and times), what you checked and what you ruled out, what you did, and what happened after. "The floor by the dishwasher was wet at 9:00, about a cup of clean water. The hose is dry. There's a slow drip from the pipe behind it. I turned off the valve and put a towel down. Still dry at 9:30." That report lets anyone carry on where you stopped.
Write things down. A problem you solved and recorded only has to be solved once.
| If | Then |
|---|---|
| The next step could cause serious damage if you're wrong | Get help before you take it. |
| You report "it's broken" | Nobody can act on that. Say what you saw, checked and did. |
Check your understanding
Turn this report into a useful one: "The water heater's acting weird."
What did you see (no hot water since 7:00, a clicking sound, a red light)? What did you check (power is on, breaker not tripped)? What did you do (nothing yet, or reset it once)? What happened after?
Key point Report what you saw, checked, did, and what happened after.
13. What you notice, and what to do
| You're sure you know what's wrong straight away | Slow down. Write down what you actually see. |
| A number or report doesn't fit | Check it before acting. |
| You fixed it, but it came back | You fixed a symptom. Find the cause. |
| You don't know where to start | List every possible cause. Check dangerous, then likely, then quick. |
| A problem started suddenly | Ask what changed just before it. |
| Two things seem connected | Ask if something else explains both. Test it. |
| You're tempted to change several things | Change one, wait, check. |
| Several things are wrong at once | Safety, stop the damage, fix the cause, clean up. |
| You've acted | Check it worked, at a time you decided in advance. |
| You're out of ideas, or the next step is risky | Get help, and report what you saw, checked and did. |
Sources
The quiz for this module opens when quiz grading goes live.