Everyday Research Methods

Patients of female doctors live longer, research shows

The study found lower mortality among patients of female physicians. Photo: PeopleImages.com - Yuri A/Shutterstock

Here's a large study that tested whether the life expectancies of Medicare patients differed, depending on whether their primary physician was a woman or a man.

The website StudyFinds reports: 

The study, published in the journal Annals of Internal Medicine, analyzed Medicare claims data from 2016 to 2019 for over 700,000 patients. They found that the mortality rate for female patients was 8.15 percent when receiving care from female physicians, compared to 8.38 percent when the physician was male. While this difference may seem small, it’s considered clinically significant by researchers.

Male patients also fared better under the care of female doctors, though the difference was less pronounced. Their mortality rate was 10.15 percent with female physicians, compared to 10.23 percent with male physicians.

A similar pattern emerged for hospital readmission rates. Patients were less likely to return to the hospital within 30 days of discharge if a female doctor saw them during their initial visit. 

a) Read the above passage carefully and identify the variables the researchers studied. Classify them on this table: 

Name of the variable (Conceptual level)	What are the variable's possible levels?	Is this manipulated or measured?

b) We might consider this a correlational study. Why?  

c) If you've read Chapter 13, you might also consider this a quasi-experiment. Why?

d) The journalist reported "They found that the mortality rate for female patients was 8.15 percent when receiving care from female physicians, compared to 8.38 percent when the physician was male. While this difference may seem small, it’s considered clinically significant by researchers."  This is a good example of how context matters when it comes to effect sizes. In your own words, explain why the difference might seem small in terms of effect size. 

e) Now, in your own words, explain why this tiny difference was considered clinically significant.

To help you make this argument, consider these values. There were 458,108 female patients in this study. The difference in 30-day mortality between male and female and male physicians was 0.24%.  Multiply this percent difference (i.e., .0024) by the number of female patients to see how many additional patient deaths there were for male physicians compared to female physicians. 
 

The empirical article, which may be behind a paywall, can be found at the Annals of Internal Medicine. 

Kids' brains while reading: Screens vs. paper

The study found that children's brains were differently active when they read on screens vs. on paper. Dasha Trofimova/Shutterstock

As a reader, you've certainly had experience reading text on both screens and on paper. You probably have a preference for one over the other. Have you ever wondered whether your brain reacts differently to these different reading formats? 

A journalist from PsyPost has reported on a study that tested this question in young readers, ages 6 to 8. The study used EEG (measured by placing a net of electrodes on the head) while children read on screens and on paper. 

Here's how the journalist described the study's method: 

Each child participated in a reading session where they were exposed to two different conditions: reading from printed paper and reading from a screen. Each condition involved reading age-appropriate expository texts followed by comprehension questions to assess their understanding. The comprehension questions served both to engage the children actively with the texts and to provide a measure of how well they understood the material under each medium.

The researchers were interested in a specific brain wave pattern called the theta/beta ratio. In lots of past research, a high theta/beta ratio has been associated with worse concentration, less attention, and more mind-wandering. The researchers wondered if the theta/beta ratios of each child would differ across the two conditions. 

a) Based on what you've read so far, what are the variables in this experiment?

Name of the variable (Conceptual level)	What are the variable's possible levels?	Is this manipulated or measured?	Is this an IV or DV?	For IVs: Is it manipulated as independent groups or within-groups?

b) What type of experiment is this? Posttest only? Pretest/posttest? Repeated measures? Concurrent measures? 

Here's the journalist's description of the study's results:

... a higher theta/beta ratio was observed during screen reading compared to paper reading. This ratio is commonly interpreted as a marker of cognitive load, suggesting that children may experience more difficulty in maintaining focused attention and processing information when reading from screens.

Together, the findings provide neurobiological evidence to support the idea that reading from a screen may impose a greater cognitive burden on children, affecting their ability to concentrate and process information as effectively as when reading from paper.

c) Sketch a bar graph of this study's results.

d)  In a design like this, it would be important to employ counterbalancing. Why? Which of the four big validities is counterbalancing addressing? 

e) In this study, children in the study read two different, age-appropriate reading passages, and they also read the texts under two different conditions. How might you arrange counterbalancing for this set of circumstances? 

The empirical article is open access, on PLOSOne. 

 

Suggested answers:

a) Based on what you've read so far, what are the variables in this experiment?

Name of the variable (Conceptual level)	What are the variable's possible levels?	Is this manipulated or measured?	Is this an IV or DV?	For IVs: Is it manipulated as independent groups or within-groups?
Reading condition	On screen, on paper	manipulated	IV	Within-groups
EEG pattern: Theta/beta ratio	Higher ratio to lower ratio	measured	DV	n/a

b) Repeated measures (it's a within-groups design, and participants' brain activity was measured as/after they read first one type of text and then another type).

c) Theta/beta ratio should be on the y-axis. The two reading conditions are on the x-axis. The bar for "on screen" reading should show a higher theta/beta ratio than the bar for "on paper" reading.

d) Counterbalancing addresses internal validity; specifically, an order effect, which is an internal validity threat that is applicable only to within-groups designs. 

e) Some children would need to read Passage A on screen and Passage B on paper, and other children would need to read Passage B on screen and Passage A on paper. Similarly, some children would need to read on screens first, followed by paper; other children would need to read on paper first, followed by screens.  In the empirical article, it is not very clear how well they counterbalanced these factors.