Okun’s law: a meaningful guide for monetary policy?
Okun’s law can be a useful guide for monetary policy, but only if the natural rate of unemployment is properly measured.>
Okun's law in recession and recovery
O kun’s law is a popular back-of-the-envelope calculation relating the growth rate of output to the change in the unemployment rate.1 Arthur Okun originally posited the law in 1962 as a means of estimating potential output. Recently, some academic studies have questioned whether the relationship still holds after the Great Recession and whether it varies across phases of the business cycle.2 The first chart shows the quarter-to-quarter change in the unemployment rate and the quarter-to-quarter percent change in output (measured by gross domestic product [GDP]) for the period 1948:Q2 through 2013:Q1. Each point on the chart represents the quarterly values of these two measurements. The blue diamonds denote observations during expansions, and the red squares denote observations during recessions. These subperiods are defined by the National Bureau of Economic Research Business Cycle Dating Com mittee, according to which recessions start at the peak of a business cycle and end at the trough. A cursory examination of the chart reveals that the relationship between unemployment and output appears to shift over the business cycle. The slopes of the lines that best fit the expansion and recession subperiods are similar (‒0.14 and –0.12, respectively); the difference across business cycle phases appears in the intercept. In addition, the slopes of the lines for the subperiods are both much flatter than the slope of the line that best fits the entire dataset (‒0.25).
The Prevalence of Dietary Supplement Use among College Students: A Nationwide Survey in Japan
To clarify the prevalence of dietary supplement use among college students, we conducted Internet-based nationwide questionnaire surveys with 157,595 Japanese college students aged between 18 to 24 years old who were registrants of Macromill Inc. (Tokyo, Japan). Among the 9066 respondents (response rate 5.8%), 16.8% were currently using dietary supplements. The prevalence of dietary supplement use did not differ significantly between males (17.1%) and females (16.7%). However, it increased according to their grade (13.1% to 20.5%), and it was higher in medical and pharmaceutical college students (22.0%) compared to others (16.7%). The main purpose of dietary supplement use was for the health benefits in both males and females. Other reasons were to build muscle in males, and as a beauty supplement and for weight loss in females. According to the purpose of dietary supplement use, the most commonly-used dietary supplements were vitamin/mineral supplements in both males and females, then protein and weight loss supplements in males and females, respectively. Although most students obtained information about dietary supplements via the Internet, they typically purchased the supplements from drug stores. Of the students surveyed, 7.5% who were currently using or used to use dietary supplements experienced adverse effects, with no significant difference between genders (8.8% in male, 7.0% in female). In conclusion, the prevalence of dietary supplement use increased with grade among college students in Japan. Some of them experienced adverse effects. Education may be important to prevent adverse effects resulting from supplement use in college.