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Chapter 1: Problem 7

What does it mean when an observational study is retrospective? What does it mean when an observational study is prospective?

Short Answer

Expert verified
Retrospective studies analyze past data; prospective studies follow subjects over time.

Step by step solution

01

- Define Retrospective Study

A retrospective study is an observational study where the outcomes have already occurred at the start of the study. Researchers look back in time to analyze data from past records to identify possible causal factors.
02

- Define Prospective Study

A prospective study is an observational study where outcomes have not yet occurred when the study begins. Researchers follow a group of individuals over time to see how different exposures affect future outcomes.
03

- Compare Both Types

The main difference between retrospective and prospective studies lies in the timing of the data being analyzed. Retrospective studies investigate past data, while prospective studies track subjects forward in time.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Retrospective Study
A retrospective study is a type of observational study. This means researchers observe and analyze data but do not intervene. In retrospective studies, researchers look back in time. They use existing data from past records or events. This data is then analyzed to identify patterns or causal factors. For example, scientists might look at medical records to study the effects of a past treatment. These types of studies can be cost-effective since data has already been collected.
Here are some key points:
  • The outcomes have already occurred when the study starts.
  • They rely on historical data or records.
  • They help in understanding trends or causes of past events.
Prospective Study
Unlike retrospective studies, prospective studies look forward in time. Researchers start with a group of subjects and follow them over a period. They observe how different exposures affect future outcomes. For example, a study may track individuals' diets over several years to see how it impacts their health. These studies can provide higher quality data because they are planned and controlled from the beginning.
Key features include:
  • The outcomes have not occurred yet when the study starts.
  • Researchers follow subjects over time.
  • They can establish a clearer cause-and-effect relationship.
Research Methodology
Research methodology refers to the systematic process used in scientific studies. It includes the strategies, methods, and techniques applied for collecting and analyzing data. Choosing the correct methodology is crucial for the validity of any research. Both retrospective and prospective studies have their methods:
For Retrospective Studies:
  • Collect existing data from records, surveys, or other sources.
  • Analyze data to identify patterns or causal factors.
For Prospective Studies:
  • Define the study group and the period of observation.
  • Regularly collect data as subjects progress through the study.
  • Analyze future outcomes to determine the impact of different exposures.
Good research methodology ensures that the findings are reliable, valid, and accurate.

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Most popular questions from this chapter

In Problems 11-22, identify the type of sampling used. A member of Congress wishes to determine her constituency's opinion regarding estate taxes. She divides her constituency into three income classes: low-income households. middle-income households, and upper-income households. She then takes a simple random sample of households from each income class.

In Problems 11-22, identify the type of sampling used. The city of Naperville is considering the construction of a new commuter rail station. The city wishes to survey the residents of the city to obtain their opinion regarding the use of tax dollars for this purpose. Design a sampling method to obtain the individuals in the sample. Be sure to support your choice.

Gallup News Service conducted a survey of 1017 American adults aged 18 years or older, September \(4-7,2014 .\) The respondents were asked, "Of every tax dollar that goes to the federal government in Washington, D.C. how many cents of each dollar would you say are wasted?" Of the 1017 individuals surveyed, \(35 \%\) indicated that 51 cents or more is wasted. Gallup reported that \(35 \%\) of all adult Americans 18 years or older believe the federal government wastes at least 51 cents of each dollar spent, with a margin of error of \(4 \%\) and a \(95 \%\) level of confidence. (a) What is the research objective? (b) What is the population? (c) What is the sample? (d) List the descriptive statistics. (e) What can be inferred from this survey?

Determine the level of measurement of each variable. Assessed value of a house

In their book SuperFreakonomics, authors Steven Levitt and Stephen Dubner describe the research of behavioral economist John List. List recruited customers and dealers at a baseball-card show to participate in an experiment in which the customer would state how much he was willing to pay for a single baseball card. The prices ranged from \(\$ 4\) (lowball) to \(\$ 50\) (premium card). The dealer would then give the customer a card that was supposed to correspond to the offer price. In this setting, the dealer could certainly give the buyer a card worth less than the offer price, but this rarely happened. The card received by the buyer was close in value to the price offered. Next, List went to the trading floor at the show and again recruited customers. But this time the customers approached dealers at their booth. The dealers did not know they were being watched. The scenario went something like this: as the customer approached the dealer's booth, he would say, "Please give me the best Derek Jeter card you can for \(\$ 20 . "\) In this scenario, the dealers consistently ripped off the customers by giving them cards worth much less than the offer price. In fact, the dealers who were the worst offenders were the same dealers who refused to participate in List's study. Do you believe that individuals who volunteer for experiments are scientific do- gooders? That is, do you believe that in designed experiments subjects strive to meet the expectations of the researcher? In addition, do you believe that results of experiments may suffer because many experiments require individuals to volunteer, and individuals who are not do-gooders do not volunteer for studies? Now, explain why control groups are needed in designed experiments and the role they can play in neutralizing the impact of scientific do- gooders.
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