Validity and Reliability

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Validity and Reliability

• A.2.4.7

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Essential Vocabulary

• validity correctness or soundness
• reliability dependability or credibility
• primary source an original source offering
  first-hand information
• secondary source information that other people
  have gathered and interpreted

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Validity
Logic is the science of correct reasoning. If
______ is true, then ______ must be true is an
example of the process of logical reasoning.
Authors whose purpose is to persuade generally
try to lead you in a way that makes you agree
with their opinions. One way they do this is by
using logical argument. By presenting reasons,
facts, and expert testimony, authors aim to have
readers say to themselves, Yes, that sounds
right.
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Validity
However, authors often make statements that
sound right but that on closer inspection are
misleading. Some types of faulty reasoning
include the following
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Validity

• Hasty generalizations coming to a conclusion
  without sufficient evidence.
• example My friends and I liked that book
  therefore, it will surely be a best-seller.
• Personal attack attacking a person who holds an
  opposing position or opinion rather than
  attacking the position itself.
• example Joe did not like the book, but with his
  record of library fines, Im not sure you should
  listen to him.

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Validity

• Either/or resenting a position as if it were
  one of only two choices available.
• example Either you love taffy, or you truly do
  not appreciate good candy.
• False cause and effect suggesting that merely
  because one event follows another, the first
  event must be the cause or source of the second
  event.
• example Since I got this new pencil, my math
  grade has improved by 10 points.

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Validity

• Here are some specific questions to ask as you
  evaluate the validity of information
• Are opinions supported with credible evidence?
• How current is the information?
• How accurate is the information?
• How objective is the information?
• What information is being emphasized and why?
• Is the information consistent and logical?

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Reliability
When you read an opinion piece in a newspaper,
you know that youre reading one persons
opinion. As a result, you may check the authors
credentials at the bottom of the article to find
out whether the person is a credible source. As
you do this, you ask yourself, Does the authors
background make him or her an authority on this
subject?
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Reliability

• Here are some specific questions to ask as you
  evaluate the credibility of information sources
• Is the author a respected authority on the topic?
  
• What are the authors motives for writing?
• What is the authors attitude toward the subject?
• What is the authors point of view on the subject?

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Reliability
As you know, not all sources are reliable.
Information in well-known encyclopedias,
almanacs, and atlases is usually reliable. One
place where you might find unreliable sources is
the Internet. When you visit a website for
factual information, check its source before you
begin reading. If its Pamelas Home Page, skip
it. If its National Geographic, read on. Sites
with Web addresses that end in the following are
often reliable sources ? .edu (education) ? .gov
(government) ? .mil (military)
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Wrong answers may be

• incorrect analysis of the validity and/or
  reliability of the passage
• facts or details that are drawn from the passage
  but are not relevant

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Practice
Atlantis Lost City Under the Sea Atlantis. A
lost civilization that sank beneath the sea in
ancient times. Truth or myth? Certainly, some
people believe Atlantis existed. For example, the
Greek writer Plato (c. 429-347 B.C.) mentioned
Atlantis twice. Plato described Atlantis as "a
great and wonderful empire" based on a large
island in the Atlantic Ocean. According to Plato,
earthquakes and floods destroyed Atlantis, 9,000
years before his own time. He claimed that this
was a true story. Some real cities have sunk
beneath the sea. However, Plato admitted he had
read about Atlantis in the records of the Greek
ruler Solon. These records were over 200 years
old. Did Plato really think it was true?
Perhaps not, since in his later writings he calls
Atlantis the kingdom of the god Poseidon.
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Practice
Scans of the ocean floor over where Plato
thought Atlantis existed have turned up nothing.
However, that has just made people believe that
Atlantis existed somewhere else. American
psychic Edgar Cayce (1877-1945) had a lot to
saywhile in a tranceon the subject of Atlantis.
He thought Atlantis was located in the Caribbean,
off the island of Bimini. In 1997, Aaron Du
Val, president of the Egyptology Society in
Miami, announced that divers had found
12,000-year-old Egyptian-style ruins off the
coast of Bimini. He did not claim that the
ruins actually were Atlantis. However, Du Val did
say, "it sure is strange how these findings not
only match Cayce's predictions but Plato's
writings as well."
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Practice
Du Val never presented images from his
expedition. But, according to geologist Eugene A.
Shinn, in an article published by the Skeptical
Inquirer magazine in January 2004, there is
indeed a structure in the waters off Bimini.
Shinn and his team analyzed the rock in the
"road" and have become convinced that it is a
natural formation. It seems like everyone has
an idea about Atlantis. Some people even believe
the Atlantis story originated in a real event
the eruption of the volcano on a Greek island,
around 1600 B.C. It is interesting to examine all
of these theories about Atlantis. However, given
the lack of evidence and the number of opinions,
perhaps Atlantis will always remain a mystery.
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Practice

• Which statement from the passage is an opinion?
• "Du Val never presented images from his
  expedition."
• "It is interesting to examine all these theories
  about Atlantis."
• "Plato described Atlantis as 'a great and
  wonderful empire' based on a large island in the
  Atlantic Ocean."
• "Shinn and his team analyzed the rock in the
  'road' and have become convinced that it is a
  natural formation."

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Practice

• Who is the most reliable source on the question
  of Atlantis being in the Caribbean?
• Eugene A. Shinn, geologist
• Edgar Cayce, American psychic
• Plato, philosopher of the 4th century B.C.E.
• Aaron Du Val, president of the Egyptology Society

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Practice

• What makes Plato a valuable source on the story
  of Atlantis?
• He wrote down accounts of the story of Atlantis.
• He lived during the time when Atlantis was
  thriving.
• He knew first hand about what happened to
  Atlantis.
• He remembered many details about where Atlantis
  was located.

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Practice

• Which statement gives the story of Atlantis the
  best evidence for being true?
• "Some real cities have sunk beneath the sea."
• "Plato described Atlantis as "a great and
  wonderful empire" based on a large island in the
  Atlantic Ocean."
• "Du Val did say, 'it sure is strange how these
  findings not only match Cayce's predictions but
  Plato's writings as well.'"
• "Some people even believe the Atlantis story
  originated in a real event the eruption of the
  volcano on a Greek island, around 1600 B.C."

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Practice

• Why is the Greek ruler, Solon, important to the
  story of Atlantis?
• He knew Plato, who was important to the story of
  Atlantis.
• His accurate records of the stories are used in
  today's research.
• He saw the city of Atlantis destroyed by
  earthquakes and floods.
• His account is, perhaps, the source closest to an
  eyewitness account.

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Assignments

• With a partner
• Read Inventions Fact or Fiction.
• Answer the five questions on your own paper and
  turn it in.
• On your own
• Read Dogs Vis-A-Vis Cats and Swing Is the Thing
  in the Focus Folder.
• Answer questions 52-55 on page 52 and turn it in.