Scientific Methodology: Background Information, Questions, Research Hypotheses, the Hypothetico- Deductive…

Scientific Methodology:Scientific Methodology:Background Information,Background Information,

Questions, Research Questions, Research Hypotheses, the Hypothetico-Hypotheses, the Hypothetico-

Deductive Approach, and Deductive Approach, and the Test of Hypothesisthe Test of Hypothesis

BIOL457BIOL45720 January 201620 January 2016

Overview of Overview of Scientific MethodologyScientific Methodology

1) Background Information1) Background Information Everything already knownEverything already known

2) Question2) Question Inspired by background info—there is always Inspired by background info—there is always somethingsomething as-yet unexplored and unknown as-yet unexplored and unknown

3) Research Hypothesis3) Research Hypothesis May (or may not) be true answer to questionMay (or may not) be true answer to question

4) Test of Hypothesis4) Test of Hypothesis Designed to attempt to falsify research Designed to attempt to falsify research

hypothesishypothesis May or may not be a controlled experimentMay or may not be a controlled experiment

5) Null Hypotheses5) Null Hypotheses Symbol: HSymbol: H00

Predictions of a lack of cause-and-effect in Predictions of a lack of cause-and-effect in data to be collecteddata to be collected

Typically several HTypically several H00’s for any one research ’s for any one research hypothesishypothesis

6) Statistical Conclusions6) Statistical Conclusions Each HEach H00 can either be… can either be…

……rejected, orrejected, or ……not rejected.not rejected.

(Notice lack of term “accepted”)(Notice lack of term “accepted”)

7) Conclusion7) Conclusion Do data and statistical conclusions…Do data and statistical conclusions…

……support research hypothesis?support research hypothesis? ……refute research hypothesis?refute research hypothesis?

8) Publication8) Publication Most commonly in a peer-reviewed journalMost commonly in a peer-reviewed journal Necessary to stimulate the cyclical nature of Necessary to stimulate the cyclical nature of

scientific methodologyscientific methodology One researcher’s data and conclusions serve as One researcher’s data and conclusions serve as

background information, inspiring another background information, inspiring another researcher’s question and/or research hypothesisresearcher’s question and/or research hypothesis

Background Background InformationInformation

Three TypesThree Types

A) Personal observation [by author]A) Personal observation [by author]

Cited as: (pers. obs.)Cited as: (pers. obs.)

May also include author’s unpublished data that relate May also include author’s unpublished data that relate toto

the study, cited as: (A. Smith, unpubl. data)the study, cited as: (A. Smith, unpubl. data)

Three TypesThree Types

B) Personal communication [from another B) Personal communication [from another researcher]researcher]

Cited as: (A. Jones, pers. comm. 2001)Cited as: (A. Jones, pers. comm. 2001)

May also include colleague’s unpublished data that May also include colleague’s unpublished data that relaterelate

to the studyto the study

Three TypesThree Types

C) Cited literatureC) Cited literature

Four major types:Four major types:1) Peer-reviewed article1) Peer-reviewed article2) Book2) Book3) Book chapter in edited volume3) Book chapter in edited volume4) Unpublished Masters thesis or Ph.D.4) Unpublished Masters thesis or Ph.D.

dissertationdissertation

HANDOUT—Colli et al. 2003HANDOUT—Colli et al. 2003

Peer ReviewPeer Review Choose a journalChoose a journal Send ms. to editorSend ms. to editor Commonly farmed out to associate editorCommonly farmed out to associate editor

Solicits 2-3 anonymous reviewsSolicits 2-3 anonymous reviews Ms. returned to authorMs. returned to author

A) Accept, following minor revisions based on reviewerA) Accept, following minor revisions based on reviewer commentscommentsB) May accept, following major revisionsB) May accept, following major revisionsC) “Thank you for considering our journal…”C) “Thank you for considering our journal…”

Timeline*Timeline* Research completedResearch completed Ms. submitted to editor a few to several months laterMs. submitted to editor a few to several months later

Generally, pre-review by 1-2 colleaguesGenerally, pre-review by 1-2 colleagues To anonymous reviewers within a monthTo anonymous reviewers within a month Back to author within a few months of submissionBack to author within a few months of submission Final acceptance a few to several months laterFinal acceptance a few to several months later Publication 6-18 months laterPublication 6-18 months later

May appear online soonerMay appear online sooner

*Much faster for *Much faster for NatureNature, , ScienceScience, certain biomedical journals, , certain biomedical journals, etc.etc.

The QuestionThe Question Inspired by background infoInspired by background info Seeks explanation of phenomenonSeeks explanation of phenomenon

The Research HypothesisThe Research Hypothesis PotentiallyPotentially correct answer to question correct answer to question

(Ergo, potentially (Ergo, potentially incorrectincorrect)) GeneralGeneral statement about nature, statement about nature, notnot one one

specific to conditions of the test to be specific to conditions of the test to be conductedconducted

May be…May be… ……strongly suggested by extensive prior theorystrongly suggested by extensive prior theory ……reasonable hypothesis based on previous studiesreasonable hypothesis based on previous studies ……a stab in the darka stab in the dark

FalsificationFalsification ““To prove”: once upon a time, this meant “to To prove”: once upon a time, this meant “to

test”test” Utah proving groundsUtah proving grounds Printer’s proofsPrinter’s proofs ““The exception that proves the rule”The exception that proves the rule”

Hypotheses can only be Hypotheses can only be disprovendisproven with with confidenceconfidence

Confidence that a hypothesis is correct comes Confidence that a hypothesis is correct comes with well-designed test(s) that fail to refute itwith well-designed test(s) that fail to refute it

The Hypothetico-The Hypothetico-Deductive Approach to Deductive Approach to

ScienceScience

Deductive ReasoningDeductive Reasoning Using several specific facts to build a general Using several specific facts to build a general

explanationexplanation Foundation for the Introduction section of a Foundation for the Introduction section of a

journal articlejournal article Discuss background info (lots of known specific Discuss background info (lots of known specific

facts)facts) Culminates in formulating research hypothesis Culminates in formulating research hypothesis

(general statement that may or may not explain a (general statement that may or may not explain a phenomenon)phenomenon)

Inductive ReasoningInductive Reasoning Assuming general explanation is true, using it Assuming general explanation is true, using it

to predict specific outcomesto predict specific outcomes Foundation for the Methods and Results and Foundation for the Methods and Results and

lead portion of Discussionlead portion of Discussion IfIf the research hypothesis is true, in a general way the research hypothesis is true, in a general way

in nature, in nature, ThenThen, one expects certain specific patterns in the , one expects certain specific patterns in the

data that are to be collecteddata that are to be collected

The Test of HypothesisThe Test of Hypothesis

Data Collection and AnalysisData Collection and Analysis Independent Variable: hypothesized cause of Independent Variable: hypothesized cause of

some effectsome effect Dependent Variable: hypothesized effect of some Dependent Variable: hypothesized effect of some

causecause Hypothesized influence: IV Hypothesized influence: IV DV DV

Controlled ExperimentControlled Experiment Independent Variable: hypothesized cause of Independent Variable: hypothesized cause of

some effectsome effect Dependent Variable: hypothesized effect of some Dependent Variable: hypothesized effect of some

causecause Hypothesized influence: IV Hypothesized influence: IV DV DV Experimental treatment(s): receive(s) IVExperimental treatment(s): receive(s) IV Control treatment(s): do(es) not receive IVControl treatment(s): do(es) not receive IV Control variableControl variabless: held : held constantconstant between groups between groups

The Advantage of The Advantage of Controlled ExperimentationControlled Experimentation

Complete isolation of potential causative Complete isolation of potential causative variable (the IV)variable (the IV)

Otherwise, correlation of DV with IV may Otherwise, correlation of DV with IV may occur because…occur because… ……IV exerts influence on DV, orIV exerts influence on DV, or ……IV and DV are actually both influenced by a IV and DV are actually both influenced by a

separate variable not under studyseparate variable not under study