# Presentation: 226806

## Marijuana Use andCollege Grades

- Lewis D. Eigen
- Higher Education Center for Alcohol and Other Drug Prevention (HEC)U. S. Department of Education&SAMHSA’s National Clearinghouse for Alcohol and Drug Information (NCADI)Center for Substance Abuse PreventionSubstance Abuse and Mental Health Services Administration*Presented at::*U. S. Department of Education’s13th Annual National Meeting on Alcohol, Other Drug, and Violence PreventionNovember 8, 1999 • Albany NY
- Social & Health Services Ltd.11420 Rockville Pike, Rockville MD 20852leigen@shs.net

## Acknowledgement

- The author wishes to thank the staff of the Core Institute and the U. S. Department of Education for carrying out the Core Survey upon which this analysis has been performed and being so generous in the sharing of their data and ideas.
- Also, the Center for Substance Abuse Prevention of the Substance Abuse and Mental Health Administration, HHS for their assistance and funding of CSAP Contract #: 277-98-6014.
- And particularly, Bob Denniston, Joan Quinlan, Cheryl Pressley, Phil Meilman, Norm Krasnagor, and Jill Herzog whose assistance is gratefully acknowledged.

**	**The views expressed herein are those of the author and do not necessarily reflect the points of view or policies of The U. S. Department of Education or the U. S. Department of Health and Human Services or any subunit thereof.  Nor are they necessarily reflective of The Higher Education Center, the National Clearinghouse for Alcohol and Drug Information, or Social & Health Services Ltd.

## Alcohol and Grades

**We know from the Core Survey reports that college grades correlate inversely with alcohol intake.**
**Is there a similar relationship for marijuana?**

## Data and Sample

**Core Survey: ****1995-97**
**197 institutions **
**93,679 students**** **

## Grade Point Equivalents

- A+ = 4.00
- A   = 4.00
- A- = 3.75
- B+ = 3.25
- B   = 3.00
- B- = 2.75
- C+ = 2.25

- C   = 2.00
- C- = 1.75
- D+ = 1.25
- D   = 1.00
- D- = 0.75
- F   = 0.00
- 	Average GPA for the entire sample = 3.03

## 30 Day Marijuana Use

*Reasonably comports with other studies of college student marijuana usage.*

## Grade Point Average

**Significant****< .001**

## Marijuana Users Have Significantly Lower Grades

**Also holds separately for:**
- Whites
- Blacks
- Native Americans
- Hispanics
- Asians
***All significant beyond the .001 level***

## Lower Grades For Different Frequencies of Use

**All significant < .001**

## Tobacco Example

**The correlation between smoking and cancer was known for years.**
**For many of those early years many claimed that there was no causality.**
- They claimed the correlation was spurious, or
- Whatever caused cancer also increased the propensity to smoke.
- A few said, “There’s just as much evidence that cancer causes smoking as the reverse.”

## Correlation & Causality

**	****If X is correlated with Y, there are 4 logical possibilities:**
**X is caused by Y.**
**Y is caused by X.**
**X and Y are BOTH caused by Z.**
**The correlation is coincidental.**

## Causality Examples

**Fetal Alcohol Syndrome is caused by drinking when pregnant.**
**In the 1800’s increase in alcohol consumption and numbers of clergy were both caused by number and type of immigrants.**

## Indicators of Causality

**	****In addition to the correlation, we look toward 2 additional factors:**
**Clinical trials or other controlled experiments.**
**Theoretical basis for the causality.**
**The strongest case can be made**** when all 3 are present!!!**

## Clinical TrialsControlled Experiments

**Not really feasible**
**Limited by**
- Ethics
- Law
- Practicality

## Theoretical Bases

**Physiological**
- e.g. Marijuana affects short-term memory
**Behavioral**
- e. g. Smoking time competes with studying

## Causality Is Not Necessarily Unique

**Alcoholism is caused by both:**** **
- Alcohol intake
- 	*as well as *
- Genetic factors

## Risk of Erroneously Assuming Causality

**We deny students the “benefits” of marijuana.**
- There are few who would argue that the benefits are particularly significant for college students – even legalizers.
**Impair the economic health of the marijuana industry.**
- Unlike the alcohol industry there is no legitimate economic interest that might be damaged.

## Risk of Erroneously Assuming No Causality

**Students average lower grades.**
**Significant higher education societal resources are wasted.**
**Some students do not graduate who would have but for ...**

## Which Error Produces More Risk & Potential Damage?

**If most of us believe that the****no causality error is the more serious, and we implement programs using the causality assumption,**
**	*****In this particular case,******there is virtually no “down side risk.”***

## Possible Social Marketing Approaches

**Increase the perception of harm (poorer grades) for students, parents, faculty, public funders, alumni and public.**
**Elevate the importance of the issue, by showing the increase in cost to society (wasted tuition, fewer skilled people in workforce, less taxes paid by workers.)**

## Parental Example

**If the institution “enables” your child to use marijuana,**
**	****The institution reduces the benefit you get for your child’s tuition.**

## Resource Example

**If grades were uniformly distributed,  marijuana would account for 6****1⁄2 percent of the average grade.**
**Take ****6****1⁄2 percent of the total cost of operating your institution and that money would be the solution to many local critical needs and desires.**

## The TAU CaseTypical American University

**30,000 students**
**$10,000 per student cost per year (cost > tuition)**
**$300 million total cost per year**
**6****1⁄2 percent is unproductive**

## TAU Result

**Almost $20 million ...****has literally gone up in smoke!!!**