Evaluating Causal Claims

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© EDB; D. Halpern, K. Ku, I. Ho, K.T. Hau 1

?Evaluating Causal Claims

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學生思維訓練課程學生思維訓練課程學生思維訓練課程2© EDB; D. Halpern, K. Ku, I. Ho, K.T. Hau

I hope the seat belt sign

is not turned on so

frequently! The plane

shakes so violently every

time it is turned on!

Is there a problem in the child’s reasoning?

學生思維訓練課程學生思維訓練課程學生思維訓練課程3© EDB; D. Halpern, K. Ku, I. Ho, K.T. Hau 3

Is There a Relationship Between Ice Cream Sales And The Number of Shark Attacks?

Months

Ice CreamSales

0

100

00

200

00

Jan 　　　　　　　 Jul 　　　　　 Dec

Months

No. of Shark Attacks

0

4

8

Jan 　　　　　　　 Jul 　　　　　 Dec


• What is the evidence?

• Is there a bias?

• Is the research approach appropriate?

Is There a Cause And Effect Relationship Between Youngsters Watching Violence Films And Their

Violent Behaviours?


Distinguish Between Fact, Opinion and Reasoned Argument

First of all, you should learn to distinguish: Fact Opinion Reasoned Argument

This is Because…

Evidence?

??! ??!6© EDB; D. Halpern, K. Ku, I. Ho, K.T. Hau

Good Thinking Requires Information and Reasons

Fact:

Tung Chee Hwa was the first Chief Executive of Hong Kong.

Opinion:

Mr Tung was a good Chief Executive.

Reasoned Argument:

Because of the differential appeals and concerns from different parties, groups and walks of life, the government should try its best to implement a policy that is favourable to all people.


I hope the seat belt sign

is not turned on so

frequently! The plane

shakes so violently every

time it is turned on!

Is there a problem in the child’s reasoning?


What is Correlation?

Months

Ice CreamSales

0

100

00

200

00

Jan 　　　　　　　 Jul 　　　　　 Dec

Months


0

4

8

Jan 　　　　　　　 Jul 　　　　　 Dec



Is there a relationship between ice cream sales and the number of shark attacks? What kind of relationship is it?



Ice Cream Sales




B rises when A rises. B falls when A rises.

Does correlation mean a cause and effect relationship?

PositiveCorrelation

NegativeCorrelation


Can You Identify the Type of Relationship?

Family Factors

Rebellious Teenager

Rebellious Teenager

Low Levels of Education

When A and B are

correlated


Rebellious Teenager




CorrelationCause and

Effect Relationship


Some Examples

Many private tutorial centres publicise the number of their students who got As or even straight As in public examinations.


• What is the evidence?

• Is there a bias?

• Is the research approach appropriate?

Is There a Cause And Effect Relationship Between Youngsters Watching Violence Films And Their

Violent Behaviours?


Attractive Product Claims

Research Example:

Is laser fat reduction treatment effective?

Results in a week!

100% Safety Approved!

Proven Effectiveness!Money Back

Money Back

GuaranteeGuarantee


Attractive Product Claims

What questions would you ask to find out if the treatment is actually effective?

Hints:

Who will be the participants?Can everyone participate in the experiment?

How to choose the participants? Do all participants receive the same treatment?


Thinking about Result of Consumer Research

Random Sampling



Laser Fat Reduction Treatment

No Laser Fat Reduction Treatment

Control Experiment

Experimental Group vs. Control Group



Other Methods of Control•Placebo •Double Blind Study

• Significance of Result (that probably happened not by chance)


How May Our Thinking Be Affected?

• What is Fallacy?- Errors in Reasoning and Logic

• Common Fallacies• Guilt by Association / Virtue by Association• Popularity & Testimonials• Weak Analogies• Appeals to Tradition


Guilt by Association andVirtue by Association

• Juvenile delinquent and reputation of school (Guilt by Association)

- If a student commits an offence, people will think that other students from the same school have bad behaviour too.

Can you think of other everyday examples of Guilt by Association and Virtue by Association?

•Favourable teacher and university (Virtue by Association)

- Your favourite teacher graduated from a certain university. Therefore, that particular university must be a good university.


Popularity & Testimonials

• Cosmetic products• Mobile phones

Can you think of other everyday examples of “Popularity & Testimonials”?

- Celebrity spokespersons and popularity terms such as “best-selling” or “most popular” are often introduced in the adverts of cosmetic products and mobile phones.


Weak Analogies

• Time spent on sports and study - Athletes train very hard for their successes. If they spend

the same amount of effort on their studies, they will get the same rewarding results.

Can you think of other everyday examples of Weak Analogies?

• A Man’s car and his girlfriend- We can infer the way a man treats his girlfriend from

the way he treats his car.


Appeals to Tradition• Husbands should work and wives should be

housewives - According to tradition, husbands are responsible for

earning money and wives are responsible for keeping the household.

Can you think of other everyday examples of Appeals to Tradition?

• School should finish early in summer - Schools used to end early in summer because of the hot

weather and the lack of air-conditioning in schools. Although most schools are now equipped with air-conditioning, we still feel that schools should end early in the summer.

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Evaluating Causal Claims…

Requires

- Effort

- Time

- and Critical

Thinking

Advantages

- Money-saving

- Wise Shopping

- Self-control

Evaluating Causal Claims

Documents

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