Quantitative research

2014-01-25 3:04 pm

Suppose you are a leader of a political party. You want to improve vote and seat shares in a federal parliamentary elections. A consultant proposed to run a larger number of ethnic minority candidates as voters want to see more diversity in their representatives. To demonstrate his claim empirically, the consultant conducted a field experiment with cooperation from your party. In the last election, he had asked your party’s local organizations to field an ethnic-minority candidate in their electoral districts (ridings). The local party organizations in sixteen districts chose to field such candidates. Your party obtained, on average, 60% vote share across the sixteen districts and won parliamentary seats in fifteen, or 95%, of the sixteen districts, while the average vote share of your party in other districts was 40% and the party won only 35% of all these districts. The consultant therefore concluded that running an ethnic-minority candidate increased your party’s vote and seat shares.

What is the most serious threat to the validity of this research design? Identify the threat, discuss why that threat is problematic, and suggest how that threat may be overcome in a perfect world (don’t worry too much about the feasibility of your proposal here; discuss an ideal situation).

回答 (1)

Cash

2014-01-31 6:58 am

✔ 最佳答案

Threats to Internal Validity in Quantitative Studies. In a nutshell Internal Validity has to do with how the study was set up and conducted including how the participants were selected and "managed: once they were in the study!I have bolded the key ones!ThreatWhat does this mean?What kind of study is most likely to effected?Temporal AmbiguityIs the independent variable really coming before the dependent variable?Do sweat pants make you fat?Comparative and correlational designs (especially if they are not prospective)History
An event that occurs during a study that can effect the responses of the participants. It could be something the participants do like start exercising all on their own or it could be an event such as an article in the newspaper or national publicity.Longitudinal. A study with repeated measures.Maturation
The participants get older, wiser, more depressed, more hungry, more tired. They change all on their own!Longitudinal studies where the participants are more likely to change such as adolescents, infants or people who are quite ill.TestingSometimes the effect being measured changes because of the number of times the participant is tested. The test itself may add to the person's knowledge or change their attitudes, hence the test becomes part of the intervention!Studies with repeated measures or a pre-test-post test design.InstrumentationThis means changes in the instrument during the study. It can also mean the data collectors get better or worse at what they are doing. To me this always seems like a reliability issue, but it is always listed under internal validity.Physiologic instruments or those in which researchers are collecting the data in person.

參考: http://www.sonoma.edu/users/k/koshar/n300/week09_intv.html

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