Validity and Reliability

Using the research article attached below describe the validity and reliability of the research. Construct a defensive two-page (using APA) paper, in which you describe possible threats to internal and external validity based on one of the following: study participants, study design, or measures used.

Please note: An abstract is not needed for this paper. The title page and reference page is not included in the two page count requirement.

Brief Report

The Effects of a Nutrition Education Intervention on Vending Machine Sales

on a University Campus

Mary V. Brown, PhD, CHES; Matthew Flint, PhD; James Fuqua, BS

Abstract. Objective: To determine the effects of a nutrition infor- mation intervention on the vending machine purchases on a col- lege campus. Participants and Methods: Five high-use vending machines were selected for the intervention, which was conducted in the fall of 2011. Baseline sales data were collected in the 5 machines prior to the intervention. At the time of the intervention, color-coded stickers were placed near each item selection to iden- tify less healthy (red), moderately healthy (yellow), and more healthy (green) snack items. Sales data were collected during the 2-week intervention. Results: Purchases of red- and yellow-stick- ered foods were reduced in most of the machines; moreover, sales of the green-stickered items increased in all of the machines. Conclusions: The increased purchases of healthier snack options demonstrate encouraging patterns that support more nutritious and healthy alternatives in vending machines.

Keywords: college students, nutrition intervention, vending machines

A s college students transition from home life to col-lege life, often there are nutrition and food chal-lenges that students may be dealing with for the first time.1 These new dietary behaviors often contribute to

the establishment of a life time of either healthy or

unhealthy behaviors.2 In a national college survey, 34.1%

of college students described themselves as overweight or

obese.3 Although obesity is a complex issue with a variety

of causes, nutrition and physical activity play a vital role in

managing energy imbalance.4

In an effort to reduce the obesity epidemic, the Centers

for Disease Control and Prevention developed the Common

Community Measures for Obesity Prevention Project,5

which was initiated to identify and recommend strategies

related to obesity prevention. The first of 24 strategies rec-

ommended healthier food and beverage choices be made

available in schools and public service venues.5 More

recently, the National Prevention Strategy unveiled in June

2011 recommended that early learning centers, schools,

colleges, and universities “implement and enforce policies

that increase availability of healthy foods, including in a la

carte lines, school stores, vending machines, and fund-

raisers.”6(p36) In addition, the Affordable Care Act now

requires calorie declarations posted near items in vending

machines, with the hope that consumers will make healthier


Several North American school districts have developed

vending machine policies that have been implemented at

the elementary and secondary school level.8–12 Policies

ranged from turning off machines during the lunch period8

or limiting accessibility to vending machines,9,10,12

decreasing the availability of unhealthy foods, increasing

availability of healthier foods,8 and ensuring foods meet

specific nutritional standards.12 Few college campuses have

nutrition policies regarding healthy vending.

Vending machines on college and university campuses

are big business. In 2012, approximately 6.6% of the 19.31

billion dollar vending industry were from the university

and college settings.13 One study that tracked meal and

snacking patterns of university students found that 74% of

Scottish students bought food and drinks from the univer-

sity vending machines.14 Students often select food based

upon convenience, taste, time, and price,2 making vending

machines a less healthy, yet quick snack.

According to the Center for Science in the Public Inter-

est, as reported in The Nation’s Health, in a survey of 251

Dr Brown, Dr Flint, andMr Fuqua are with the Department of Public and Community Health at Utah Valley University in Orem, Utah.

Copyright � 2014 Taylor & Francis Group, LLC



schools, 73% of beverage options and 83% of snack options

were of poor nutritional quality.15 In a study of 11 US col-

lege campuses, researchers found that the majority of bev-

erages and snacks were low in fiber, and high in calories,

fat, and sugar.16

Several interventions have been implemented in vari-

ous settings to increase the purchase of nutritious food

in vending machines. For example, increasing the num-

ber of nutrient-dense snacks and including nutrition

information resulted in a decrease in sales on one uni-

versity campus.17 Educational materials including labels

and signs placed on vending machines located in

teacher’s lounges on elementary and middle school cam-

puses promoting low-fat items increased the sale of the

healthier items, but did not reach statistical signifi-

cance.18 Another intervention included environmental pol-

icies such as eliminating regular soda beverages and

decreasing the hours of vending machine operation, which

resulted in a decrease in revenue and commissions in one

school district.8 In addition, providing healthy vending

choices and nutrition information in the worksite19 as well

as the health care setting20 has increased as consumers

demand healthier options. The results of these studies

became the impetus for this study.

This study aimed to determine the effects of a simple

nutrition information intervention on the vending

machine purchases on a college campus. The “Navigate

the Snack Debate” intervention was developed by a

group of undergraduate public and community health

students as an engaged-learning project. Our hypothesis

was that our intervention would increase the purchase of

healthy foods and decrease unhealthy foods purchased

at the vending machine.


This study was conducted at a large western public uni-

versity with a student population of 32,000. Although the

Institutional Review Board was contacted, approval was

not necessary to collect data regarding the sales of food

items in the vending machine. The university Dining Serv-

ices Director selected 5 snack vending machines out of the

22 machines (22.7%) on campus. The 5 machines that were

selected were in high-traffic areas and considered “high

use” by Dining Services (one was located in the library, 2

in the Liberal Arts Building, and 2 in the Physical Educa-

tion Building). The unrefrigerated vending machines held

between 35 to 40 snack items each. Prior to the start of the

study, each of the food items in the vending machines were

assessed for their calories, total fat, and saturated fat based

upon the nutrition label. The nonexperimental pretest/post-

test design included a 2-week baseline period that tracked

the sales from all 5 of the machines. All data were collected

early in the fall semester to avoid any special activities (fall

break, basketball season) that might have an impact on

vending sales.


Following the baseline data collection period, each item

received a color-coded sticker based upon the “traffic light”

system of red, yellow, or green. Criteria for the color code

was developed using the United States Department of Agri-

culture (USDA) Dietary Guidelines for Americans 201021

and the USDA Foods of Minimal Value22 because of their

use in previous vending research23,24 as well as recommen-

dations from a registered dietitian (Annette Mica, MS, RD,

LD, e-mail communication, July 2011). Items that received

the red sticker contained more than 250 calories per serving

and/or more than 40% of calories from fat and/or more than

10% of the calories from saturated fat. The yellow-stick-

ered items contained less than 250 calories, but had 30%–

39% calories from fat and/or 5%–9% of calories from satu-

rated fat. The green-stickered items also contained less than

250 calories but had less that 30% of the calories from fat

and/or less than 5% of calories from saturated fat. Two

researchers coded the machines together to ensure accu-

racy. Although it is recognized that these nutritional criteria

are not all encompassing, for example, sodium, fiber, and

sugar were not taken into account, the criteria do provide a

basis for selection categorization. Moreover, healthier fats

such as nuts were still given a red sticker because of the

high calorie count. This corresponds with the Nutrition

Environmental Measures Survey tool, which also places

nuts in the red category.25

In addition to the colored sticker placed next to the food

item in the vending machine, a vinyl sticker approximately

8 by 12 inches was posted on the front panel of each vend-

ing machine, just above the selection button. The vinyl

sticker explained what the 3 color-coded stickers indicated

and gave the brief nutrition information about each colored

sticker. Finally, 11- by 14-inch posters developed by public

health students and the university marketing department

were placed around campus encouraging students to select

the green colored items with a slogan of “Go ahead, eat and

enjoy.” The yellow colored items stated “Caution, eat mod-

erately,” whereas the red color indicated “Stop, eat


Once the educational materials were in place, the sales of

each item were then tracked for an additional 2 weeks. Dur-

ing this time frame, the number of red-, yellow-, and green-

coded items remained consistent. As the data were col-

lected, the number of sales for each food item was input

into an Excel spreadsheet.

Data Analysis

Data were analyzed using the Statistical Package for

Social Sciences (SPSS) version 19.0 for Windows (SPSS,

Chicago, Illinois). A paired-sample t test was used to mea-

sure sales in each of the 5 vending machines comparing

baseline sales to intervention sales. A paired-sample t test

determines differences in means and whether they are sig-

nificant.26 A significant difference in means can indicate

Nutrition Education Intervention and Vending Machine Sales

VOL 62, OCTOBER 2014 513

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