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Spurious Relationship
A correlation between two
variables that have no
causal relationship; both
variables are caused by
another variable
Scatterplot illustration of a spurious
relationship
Only small
fires
Fire
trucks
Only large
fires
Fire Damage
Fire
trucks
Fire Damage
Fire Damage
All Fires
Fire
trucks
Scatterplot illustration of a spurious
relationship
Babies
All months
Storks
Only spring
and summer
months
Babies
Storks
Babies
Only fall
and winter
months
Storks
Reconciliation
Example of correlation
Truth
Solution
Logic: deep concern about the logic of the causal
mechanism
Does truth lead to reconciliation?

Reconciliation:

I find it difficult to understand the customs and ways of [the opposite racial group].

It is hard to imagine ever being friends with a [the opposite racial group].

More than most groups, [the opposite racial group] are likely to engage in crime.

[The opposite racial group] are untrustworthy.

[The opposite racial group] are selfish, and only look after the interests of their group.

I feel uncomfortable when I am around a group of [the opposite racial group].

I often don't believe what [the opposite racial group] say to me.

South Africa would be a better place if there were no [the opposite racial group] in the country.

I could never imagine being part of a political party made up mainly of [the opposite racial group].
Does truth lead to reconciliation?

Truth:

Apartheid was a crime against humanity. (True).

There were certainly some abuses under the old apartheid system, but the ideas behind apartheid were
basically good ones. (False)

The struggle to preserve apartheid was just.

(False) Both those struggling for and those struggling against the old apartheid system did unforgivable
things to people. (True)

The abuses under apartheid were largely committed by a few evil individuals, not by the state institutions
themselves. (False)
An illustration with a causal model
A and B are
spuriously
correlated if:
A and B are NOT
spuriously
correlated if:
Z
A
Z
B
A
B
A test of whether A and B are spurious


Look at the relationship between A and B,
controlling for Z
This means, that for all values of Z, you
should look at the relationship between A
and B.
Scatterplot illustration of a spurious
relationship
Only racists
Truth
Reconciliation
Truth
Reconciliation
Reconciliation
All South Africans
Only nonracists
Truth
Explaining Venn Diagrams
Variance
Reconciliation
Explaining Venn Diagrams
Variance
Truth
Explaining Venn Diagrams
Variance
Racism
Plot showing positive
covariance
Mean urban %
Mean female literacy
Plot showingMean
negative
covariance
calorie intake
Mean infant mortality
Plot showing
no covariance
Mean GDP
Mean crop
production
Venn diagram showing truth is only
spuriously related to reconciliation
Truth
Racism
Reconciliation
Scatterplot illustration of a spurious
relationship
Only racists
Truth
Reconciliation
Truth
Reconciliation
Reconciliation
All South Africans
Only nonracists
Truth
Scatterplot illustration of a relationship
that is {not necessarily} spurious
Only racists
Truth
Reconciliation
Truth
Reconciliation
Reconciliation
All South Africans
Only nonracists
Truth
Venn diagram showing truth has an
independent impact on reconciliation
Truth
Racism
Reconciliation