Table 1 Existing studies and opportunities for quasi-experiments

From: Quantifying causality in data science with quasi-experiments

Instrumental variable
Domain area Question Treatment (X) Instrument (Z) Outcome (Y)
Economics Does required schooling influence future wages25? Required schooling Birth season Future job earnings
Medicine Using genome-wide association study data, what is the relationship between cholesterol and cardiovascular disease60? High-density lipoprotein (HDL) cholesterol levels Variation in thousands of genes that affect HDL cholesterol levels Coronary artery disease and heart attack risk
Industry How do product recommendations affect what products customers view58? Product recommendation Shock in popularity to product next to recommended product Click-through rate on the recommended product
Society Does sleep deprivation result in more car accidents92? Sleep amount Daylight savings time Vehicle crash statistics
Neuroscience Are neurons A and B causally connected to each other93? Optogenetic stimulation of neuron A Random refractory periods of other neurons Whether neuron B fires
Regression discontinuity designs
Domain area Question Treatment (X) Running variable (R) and cutoff (T) Outcome (Y)
Education How does academic recognition affect future academic success32? Certificate of Merit recognition NMSQT test score and minimum score needed for Certificate of Merit eligibility Subsequent scholarship awards
Medicine When should HIV patients get started on antiretroviral therapy94? Antiretroviral therapy CD4 T-cell count and threshold for treatment administration Mortality
Industry How much does being on the first page of search results influence click-through? Website link on first page of search results Search result ranking and first page display limit Click-through rate on links
Society How does air pollution influence life expectancy95? Air pollutants from burning coal Distance from river and free coal government policy north of the river Life expectancy
Neuroscience How do neurons learn to optimize their activity96? Neuron spiking Input neural drive and spiking threshold Observed reward for neuron
Difference-in-differences
Domain area Question Treatment (X) Parallel groups Outcome (Y)
Economics Does increasing the minimum wage decrease employment43? Increased minimum wage in New Jersey Fast food workers in New Jersey and Pennsylvania Employment after minimum wage increase
Medicine How does limiting hospital work hours affect surgical outcomes97? Limiting resident duty hours to 80 hours a week Teaching and non-teaching hospitals, with/without residents Patient mortality, re-admission after duty hours limit
Industry How does social media presence influence company profitability98? Company launch of social media site Participating and non-participating customers Customer site visit frequency and profitability after social media site launch
Society Does seeing advertisements make people unhappy? Social media site incorporating ads into their app Users and non-users of the social media platform Well-being and sentiment measures after ads
Ecology How do wildfires affect plant species diversity99? Wildfires burning plots of land Burned and unburned geographically similar land plots Measurements of plant species richness