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Evaluation of a theory-based public health intervention to promote
healthy dietary habits in university students
Option 1 – Research Proposal
Course: KIN 330
Term: Winter 2007
Jacqueline Leung // 20171141
Katy Lo // 20173042
Chris Tsoi // 20091735
Joanna Wu // 20169917Abstract
The problem of unhealthy dietary habits in university students has been the subject of
many public health interventions in the past, which have been met with mixed success. This
study will determine the effectiveness of a new intervention which improves on past designs by
explicitly and simultaneously affecting multiple pathways to behavior change. Evaluations will
be conducted using standardized and validated survey instruments within the framework of a
between subject, randomized multi-group pretest and posttest control group design to determine
change in dietary choices, nutritional knowledge, and attitudes towards healthy eating. The
intervention is expected to show significant improvement in all three areas.
Introduction
The research project described in this proposal aims to investigate the effect of a theorybased intervention on the dietary habits of university students. This is an important area of study
because students often fail to make healthy nutritional choices (Misra, 2000). Von Ah (2006)
reports that a lack of basic nutritional knowledge and appreciation for the importance of healthy
eating is compounded by the high levels of stress which students experience in university. This
phenomenon is particularly injurious in first year, a time of transition where students may face
financial pressures, challenges to their time management ability, and an academically imposing
course load. Under such circumstances, it is almost inevitable that a student with little nutritional
knowledge who fails to find healthy eating important will start to develop poor dietary habits.
There is little disagreement in the literature that such habits lead to undesirable health
outcomes. For instance, Huang et al. (2004) found that 25% of cancer-related deaths were
attributable to poor dietary choices, such as a high-fat/low-fiber pattern. Whitney and Rolfes
(2005) also comment that obesity is often a consequence of poor diet, and in turn can lead to
cardiovascular conditions such as high blood pressure and high cholesterol. An intervention to
improve students’ dietary habits during such a formative time in their lives, then, is well
justified.
In preparing and planning this research study, the literature on past dietary interventions
was extensively reviewed. The purpose of the review was to consolidate existing knowledge of
nutrition intervention effectiveness to inform the development of the intervention at the heart of
this study. It was found that interventions tended to focus on one of three routes to behavior
change: cognitive (increasing participants’ knowledge about nutrition), behavioral (direct
modification of behavior), or affective (changing participants’ emotions and feelings towards
healthy eating).
Firstly, cognitive or “knowledge-based” approaches to nutrition intervention programs
were found to be effective. Klohe-Lehman (2006) found that with weight-management
programs, nutrition education was a strong predictor of effective weight control. Furthermore,
favorable weight loss in obese and overweight low-income mothers was found to be related to
the extent of their nutritional knowledge. In another study, a 4-month intervention that used
newsletters and computer-based communication to increase fruit and vegetable consumption by
college students aged 18 to 24 years was found to be highly successful, as the experimental
group showed an increase in vegetable and fruit consumption which was significantly greater
than that observed in the control group (Richards, Kattelmann, & Ren, 2006).
Frenn (2003) found that classroom-style nutrition instruction was also effective. Students
in a treatment group who received classroom and environment interventions showed
improvements from baseline for their usual food choices (such as a greater tendency to choose
lower fat foods), whereas students receiving the environment intervention only and those
receiving nothing at all showed no changes in their usual food choices scores. Lastly, an
expansive study on the effects of the 1990 Nutrition Labeling and Education Act, which allowed
the FDA greater control over the accuracy of health claims on food labels, found that customers
who were able to understand and use the label information showed healthier purchasing
behaviors (Marietta, Welshimer, & Long Anderson, 1999).
Secondly, there was much found in the literature to support an affective-based nutrition
intervention. Specifically, McKinley (2006) found that the greatest barrier encountered in
encouraging healthier dietary habits in young adults was in convincing them that a healthy diet
was an attractive and attainable lifestyle. Other relevant factors were the subject’s emotional
responses to the taste and appearance of food, time and effort required to prepare the food,
choice and availability of food, and the perceived relationship between the food and their body
image.
Many affective-based interventions involve the principle of cognitive dissonance, which
is an internal feeling of discomfort and unrest resulting from a discrepancy between two beliefs,
or between a belief and a behavior. Leary, Tchividjian, and Kraxberger (1994) reported the
success of interventions which induced students to develop positive feelings about healthy eating
behaviors. When these feelings were juxtaposed with the subjects’ unhealthy behavior patterns,
they often resolved the conflict by changing their behavior.
Researchers have also found success in using a corollary of the cognitive dissonance
concept: when the idea or attitude presented to a person is compatible with their existing beliefs,
they are highly likely to adopt it. This was put into practice by Fulkerson, French, and Story
(2004) who noted that adolescents seeking to lose weight had highly positive attitudes towards
low-fat foods. The unsurprising result of a subsequent study was that dietary improvement
interventions focusing on the increased consumption of low-fat foods were more successful than
those highlighting other aspects of healthy eating behavior, such as eating more fruits and
vegetables.
Thirdly, some dietary interventions are based on the direct manipulation of behavior,
rather than indirectly through increasing knowledge (cognitive) or altering emotions (affective).
These interventions are usually derived from behavioral change theories such as B.F. Skinner’s
operant conditioning (1938), where it is believed that the results of a person's behavior will
increase or decrease the likelihood of that behavior occurring again in the future. Horne, Lowe,
Bowdery, and Egerton (1998), for example, describe a particularly successful intervention where
children who received rewards for eating fruits and vegetables demonstrated a marked and longlasting increase in consumption of these healthy foods.
The intervention created for this study utilizes the strengths of the studies described in the
literature review, and then attempts to improve on them in a crucial area. The strengths of the
studies are in their faithful application of theoretical and experimental findings to the created
interventions. Our intervention will do the same: it is based on elements and constructs from
Social Cognitive Theory and the Health Beliefs Model. This act of using multiple theories as the
basis for our intervention, though, is where it departs from most interventions attempted in the
past: where interventions have historically relied on the manipulation of a single pathway
(cognitive, affective, or behavioral), our intervention will address all three elements at once. This
is possible because the aforementioned constructs and theories collectively encompass each of
the affective, behavioral, and cognitive pathways to change. Towards this end, findings by Zanna
and Rempel (1988) are encouraging as they show how addressing all of the pathways at once
result in a synergistic effect that is powerful in changing a person’s overall attitude – and thus
his/her habits – towards a practice such as healthy eating.
Given this data, we expect that our intervention will be successful in creating or
reinforcing a healthy eating lifestyle for the student participants. The main outcome variable of
interest will be their actual dietary choices (the behavior pathway), but their nutritional
knowledge (cognitive pathway) and attitudes towards healthy eating (affective pathway) will be
measured as well. We expect that subjects receiving the intervention will show improvements in
these areas which will be (statistically) significantly greater than anything seen in the control
group. Furthermore, because of the comprehensive nature of the intervention in addressing all
three pathways, changes in one are expected to be highly correlated with changes in the others.
Methods
Research Paradigm
We will be using an online survey tool to investigate the effect of a video-based
intervention on the healthiness of subjects’ dietary choices, as well as the extent of their
nutritional knowledge and their attitudes towards healthy eating.
Variables of Interest
The independent variable is the healthy eating intervention. It will be administered to the
experimental group and withheld from the control group. The dependent variables are students’
dietary choices, nutritional knowledge, and attitudes towards healthy eating.
The healthy eating intervention is a series of short television programs which will include
dramas, informational presentations, and instructional sessions. These three types of
programming collectively incorporate principles and constructs from Bandura’s Social Cognitive
Theory and the Health Beliefs Model (most recently modified by Becker and Janz) in providing
programming designed to affect subjects along the affective, behavioral, and cognitive pathways.
The affective component of the television programs is delivered mostly through fear
appeals. Fear appeals are deliveries of information designed to make the subject worried or
afraid as a result of imagining some sort of bad outcome. They are then highly motivated to
change their behavior to avoid the undesired consequence (Baranowski, 2003; Michie &
Abraham, 2003). In this intervention, fear appeals are made chiefly in two ways: firstly,
informational presentations are given which explain the health burden created by poor dietary
habits as well as the economic, psychosocial, and other practical consequences of ill health. This
strategy is also related to the Health Beliefs Model, which states that if a person believes that
failing to perform a healthy behavior will lead to severe negative consequences, he/she will tend
to change their behavior in an attempt to avoid this.
Secondly, actors in the dramas who make poor dietary choices will be shown suffering
negative health consequences as a result. This part of the intervention was inspired by the
vicarious experience construct of Social Cognitive Theory, which states that people can take on
beliefs and adopt attitudes about the outcomes of certain behaviors if they observe other people
experiencing them – they need not experience anything themselves. The utility of this within the
context of a health intervention is well-established (Allensworth, Lawson, Nicholson & Wyche,
1997).
The behavioral component of the television programming is delivered through another
facet of the Social Cognitive Theory: modeling. This construct states that when people observe
others performing behaviors which result in positive outcomes, they will be motivated to imitate
the behavior of the model and furthermore can use the model’s example to understand how the
behavior is performed (this is vicarious learning). We will take advantage of this tendency with
our intervention: actors in the dramas will be shown making positive choices and reaping the
resultant rewards.
Social Cognitive Theory also states that imitation of behavior is more likely to occur if
the model is either of high status or perceived to be similar to the subjects. This important fact is
carefully considered in the intervention: the actors will be fellow students or professors whom
the students look up to as authoritative and wise.
Lastly, the television programs will contain components aimed at affecting the cognitive
pathway to behavior change. This is fairly straightforward: it will involve the visual and verbal
transfer of information. The theoretical basis for this strategy is found in the Health Belief
Model, which says that the benefits which a person perceives will result from a behavior and the
perceived barriers to performing that behavior will affect the way in which the person in question
actually behaves.
Education and traditional knowledge transfer can be instrumental in these areas because a
barrier to performing behavior is frequently a lack of knowledge of how it can be done – for
example, how to cook a healthy meal or how to read nutritional labels. The perceived benefits for
eating healthily can also be communicated through traditional knowledge transfer: the television
programs will include information about how eating healthily can improve academic
performance, increase alertness, save money, and so on.
The first dependent variable, dietary choices, will be operationally defined as the
subject's adherence to the healthy eating guidelines given in Nutrition Recommendations...A Call
for Action, a summary report from the Canada's Department of National Health and Welfare
(1989) which subsequently provided the basis for Canada's Guidelines for Healthy Eating. The
report was the result of research into areas such as what the optimum percentage of caloric intake
should be from fat, or what the required amount of Vitamin C should be in order to avoid
deficiency. The recommendations given are based on these findings. Because these
recommendations are evidence-based and essentially serve as national standards, they are
suitable as operational definitions for the variable of dietary choice. This measure will be
quantified by counting the number of guidelines which the subject shows adherence to.
The second dependent variable is nutritional knowledge, which is important because it
allows one's desire to eat healthily to be actualized. Parmenter and Wardle (1999) argue that a
functional knowledge of nutrition can be divided into four main areas: basic knowledge of
dietary recommendations, awareness of the nutrients provided by certain foods, ability to identify
the overall healthiest food amongst an array of choices, and knowledge of the health implications
of eating or failing to eat certain foods (Parmenter & Wardle, 1999). Thus, nutritional knowledge
will be operationally defined as the score one receives on a test designed to evaluate knowledge
in each of these areas. Content and face validity for the test are expected to be high because the
cognitive component of the intervention intends to explicitly address these areas as well.
The third dependent variable is attitude towards healthy eating. This variable
encompasses the subjects' intentions and emotions towards many different aspects of healthy
eating. The ones targeted for research, however, are those which have been shown to be related
to health. A review of the literature reveals many different aspects of healthy eating attitudes
which have been shown to be of significant consequence to overall health and actual dietary
choices. These include the importance of staying current with nutritional science by reading
books and magazines, opinion of the benefit of foods labeled "low fat" or "diet" (Ralph, Seamen,
& Woods, 1996), the meaning and importance of healthy eating (Akamatsu, Maeda, Hagihara, &
Shirakawa, 2005), willingness to pay more for healthier foods, and trusted sources of information
on healthy eating (Lappalainena, Kearney, & Gibney, 1998). The attitude towards healthy eating
will be defined as the score which the subject receives on a test whose question items sample
these categories.
Participants
In designing this study, the ethical implications of the participant recruitment technique,
the intervention itself, and the data-gathering process were fully considered. The guidelines
listed in the Tri-Council Policy Statement were used to identify three important ethical issues to
address: confidentiality/anonymity, harm, and deception.
Firstly, confidentiality and anonymity were ethical concerns which the study design paid
particular attention to. We ultimately decided to use a partial-anonymity model: although the
questionnaire will be completed online and thus the subjects will be kept unaware of the
identities of other subjects, the researchers will have access to personal information. This is
because the study requires the same participants to complete and return a total of three
subsequent questionnaires, and so their student number and email address must be known to
facilitate future contact and to match the three surveys together for each subject.
Secondly, with respect to harm, the study is not expected to pose any problems: the datagathering methods and the intervention itself are non-invasive. Specifically regarding the
intervention, neither the control group nor the experimental group are put at any elevated risk by
receiving or not receiving the intervention. The control group will not experience the removal of
any materials conducive to healthy eating which are already present in the cafeteria environment.
Likewise, the experimental group will not receive any treatment which could negatively affect
healthy eating; instead an environment will be created in which students have the opportunity to
become more aware of nutritional concepts and develop healthy eating habits.
Thirdly, this study uses deception as part of its data-gathering methods – no participant
will be informed that the healthy eating television programming is part of a study. Instead, the
information sheet will merely state that its purpose is to look at the eating habits of university
students. The rationale for this is our desire to avoid social psychological phenomena such as
“control group behavior”, whereby a control group behaves differently because they are aware
that they are being deprived of a treatment being received by the experimental group, thus
invalidating the experiment. Also, we would like to avoid the tendency of participants
responding to the questionnaire in a way that would please the experimenter.
There will be an informational document provided upon the final questionnaire which
will describe the study in full, including a confession to the deception and an explanation of why
it was necessary. Unfortunately, the anticipated breadth of the study will preclude the
experimenters from personally delivering this information and answering follow-up questions
immediately, but the document will list contact information for the experimenters and encourage
the subjects to write if they have any additional questions. Also, it will give instructions for
accessing the study results when available.
Finally, the study will not commence until it has passed review by the Office of Research
Ethics and the Human Research Ethics Committee.
The sample group for this study will be composed entirely of first year students at the
University of Waterloo who live in either Village 1 or Ron Eydt Village. Since the Department
of Housing and Residences does not allot residence assignments to first year students on the
basis of age, ethnicity, or program of study, each group will be randomized with respect to these
variables and are therefore assumed to be representative of the overall population (first year
university students).
All participants in this study will be volunteers, and it is acknowledged that those who
volunteer are frequently well-educated, intelligent, and of higher social class. However, the
reality of Canadian society today is that these traits are generally true of all university students.
Thus it is doubtful that the characteristics of the participants will represent a significant departure
from the characteristics of the population whom we wish to extrapolate their results to. As well,
due to the confidentiality of this study, people will be unable to tell if their classmates have
participated in it, and so there will not be any social pressure affecting the decision to complete
the questionnaire .
Materials
The test will consist of 3 parts - one for each of the dependent variables. Other
researchers have already developed and validated tests for evaluating each of the areas, so their
work will be adopted and extended for the purposes of this research project.
Firstly, subjects will be asked to complete a web-based food intake assessment developed
and validated (face and content validity) by McCargar, Hanning, Jessup, and Lambraki (2003).
The survey is designed to gather data about dietary habits which can be directly used in a
nutrition analysis program such as ESHA Research's Food Processor SQL. This program will be
used to analyze variables such as caloric distribution, total calories consumed, and sodium
content and can thus provide an indication of the extent to which the diet complies with the
Nutrition Recommendations for Canadians (Health Canada, 2004), which has been used as the
operational definition for dietary habits, as discussed in the previous section.
Since the survey by McCargar et al. (2004) relies partially on a 24-hour recall of food
eaten, a single administration of it does not allow for unrepresentative data - for example, a
subject whose 24-hour recall reveals excessively high alcohol intake only because he was
attending a birthday party. As well, it is recognized that self-report measures suffer from
unreliability due to participants' forgetfulness. To rectify these concerns, the Iowa State
University Foods method will be applied to the results. It is a statistical method which accounts
for the limitations and inaccuracies of single 24-hour recalls better than multiple administrations
of the test can (Dodd, Guenther, Freedman, Subar, Kipnis, & Midthune, et. al, 2006).
Secondly, subjects will be asked to complete an academic-type quiz to assess their level
of nutritional knowledge. Question items will be taken from the questionnaire developed by
Parmenter and Wardle (1999), and will be unique from pre-test to post-test so that testing effects
are unable to limit internal validity. The questionnaire has been extensively tested for content
validity and ability to evaluate its four main areas of focus: basic knowledge of dietary
recommendations, awareness of the nutrients provided by certain foods, ability to identify the
overall healthiest food amongst an array of choices, and knowledge of the health implications of
eating or failing to eat certain foods (Parmenter & Wardle, 1999).
Subjects will be explicitly requested to not consult any resources while performing the
test, so that their score is an accurate indicator of what their own level of knowledge is. To this
end, they will be told that the test scores will not be used for any form of evaluation, but simply
rather as research data.
Thirdly, the test will evaluate the subjects' attitudes towards the most relevant issues
surrounding healthy eating. This will be accomplished using questions which consist mostly of
opinion statements, and that the subjects will answer using a Likert scale to indicate the extent to
which they agree or disagree.
In designing the 3-part test, the major barriers to reliability and validity were considered:
unrepresentative subject groups, the social desirability bias, and unreliable questions. Each of
these was controlled for in the manner described below.
Firstly, it is recognized that subject characteristics such as socioeconomic, demographic,
and lifestyle factors affect each of the dependent variables (Deshmukh-Taskar, Nicklas, Yang, &
Berenson, 2007). Although the experimental design will significantly limit the extent to which
these factors can confound the results, the survey will also include basic questions to assess these
categories so that any variability explained by them can be ascertained. The issues which these
queries will specifically address include physical activity level, ethnicity, and gender, which
have been found by Deshmukh et al. to make significant differences.
Secondly, the desire to cast one's attitudes in a better light is recognized, and will be
addressed by the Marlowe-Crowne Social Desirability Scale (Strahan and Gerbasi, 1972), which
provides an indication of the extent to which an individual has a need for approval and would
thus alter his responses on questions such those presented in Section 3. If, according this scale, a
subject’s responses can be expected to be significantly skewed due to this bias, they will be
discarded.
Lastly, a split-half analysis will be performed on the test to ensure that questions relating
to the same issue produce answers which are highly correlated with each other. This will help to
ensure that the test is reliable.
Procedure
This is a longitudinal study that takes place over a span of 3 years. The procedure is
adapted from a between subject, randomized multi-group pretest and posttest control group
design. It will follow two groups of students throughout the entire study: the distribution of the
students into groups will occur through the random allocation procedure employed by the
Department of Housing and Residences. Questionnaires will be deployed before and after the
intervention to test treatment effects and to maintain internal validity. As well, a final third
questionnaire will be given after three years to assess the long term effects of the intervention.
At the beginning of the study, the first questionnaire will be administered, along with an
information sheet describing the purpose of the study and its longitudinal nature.
Implementation of the first questionnaire will prior to the beginning of the year during the
residence application process, after their acceptance to the university has been confirmed. This
first data set will hold initial information for each of the participants and provide a benchmark to
compare later results against.
The same questionnaire will be given to both sets of students, but only one cafeteria will
contain the intervention (Ron Eydt Village) - the other (Village 1) will continue as normal.
This arrangement was chosen because of the spatial relationship between the cafeterias: since
Village 1 is located between Ron Eydt Village and the main campus, students from Ron Eydt
passing through Village 1 would be exposed to, and affected by, the environment of their
cafeteria. Conversely, Village 1 students would rarely have reason to venture to Ron Eydt
Village (exceptions to this behavior will be grounds for exclusion, as explained in the
“Hypothesized Results” section). Given this, it is logical to place the control group in Village
1.
Instead of administering the questionnaire by paper, it will be given online on UW-ACE,
in a similar format to many of the other questionnaires needed to be filled out prior to first
year. This decision was made because it will expedite the data collaboration process and be
more convenient for the students: the questionnaire can be finished whenever they have time,
and does not require them to hand it in or mail it anywhere. External studies provide assurance
that an internet survey will produce results similar to those with more traditional approaches.
The questionnaire will be available at the beginning of July before entering University, and end
at the end of September.
After the first questionnaire has been administered, the intervention will begin. As stated
earlier, those at Village 1 will carry on with regular cafeteria food, whereas Ron Eydt Village
cafeteria will implement our intervention. This entails showing the television programming
(described in the “Variables” section) in the Ron Eydt Village Cafeteria during meal times on
multiple screens placed around the cafeteria and dining area. These locations will include the
area where food is purchased – it is expected that students waiting in line with nothing else to do
will watch the screens with high attentiveness. Also, in the main dining area, the majority of the
tables and chairs in the cafeteria will be oriented towards a screen in an effort to promote
increased interest and viewership. Lastly, because of the varying times that students eat, the
program will commence at 7am when the cafeteria opens and will repeat throughout the day until
7pm when the cafeteria closes.
After their first year is complete the intervention will end, and a second questionnaire
will be administered prior to leaving residence. Once again, the questionnaire will be posted on
UW ACE at the beginning of exams in April, and will end at the end of August. This time frame
will accommodate students who choose to answer immediately after or during exams, as well as
those who may fail to see the questionnaire until they register their courses for the next term.
However, this second survey will be sent out to fewer people: only those who completed
the first survey will have access to it. As stated earlier, these people will be identified through
the use of their student ID and email address. Although the question items will remain the same
(with an important exception, see “Materials”), an extra question will be included in this survey
to assess the cafeteria in which the subject ate the most. This question will help experimenters to
be aware of whether students in the experimental group were in fact exposed to the treatment,
and whether control group participants did not experience the treatment to any significant degree.
Lastly, as with the first questionnaire, a brief paragraph will be included to remind
students of the study they are involved in, and that one last questionnaire would be given in three
years’ time. After the second questionnaire closes, analysis of the short term intervention effects
will be possible.
The final step in this study will be to administer one last follow-up questionnaire to test
the long term effects of our intervention. Once again, the list of participants is becomes narrower,
because this list is based on the number of people who filled out the prior questionnaires.
Questionnaires will go on UW-ACE in August of their third year; one year after the second
survey is closed. It will stay online until December of the same year. This time period allows for
all regular and co-op streams to see it on their UW-ACE. Like the first two questionnaires, a
summary paragraph will be included with this questionnaire. Since deception is used, this
paragraph will include debriefing information, including why deception was used, and how to
access study results if they are interested.
After the closing questionnaires in December the final statistical analysis will be run for
the study to see the long term effects of an intervention like this.
Hypothesized Results
Due to the past success of theory-based interventions for improving healthy eating
behavior, and our attempts to improve on these interventions by combining all three pathways
(affective, behavioral, and cognitive), we expect that a significant increase will be observed for
all three dependent variables. Since the experiment involved manipulating the intervention
variable and controlling for other confounding variables, we will be able to conclude that there is
a causal relationship between the presence of our intervention and the increase in healthy eating
behavior. Graphical illustration of these results is provided in the appendix.
The trends illustrated in the graphs provide the basis for additional commentary on three
issues: the change observed in the control group, the validity of the improvement observed in the
experimental group, and the correlation between the three dependent variables.
The control group in this study was meant to aid in defining error or cohort effects in our
study. That is, by including a control group, we were able to see whether our intervention was
the true reason for the observed increase in healthy behavior. In a carefully controlled lab
experiment over a shorter period of time, it could be expected that the control group would show
no distinct pattern of change. However, since this is not the case with our study, some change is
expected.
Secondly, it is worthwhile to consider some alternative reasons for the increase in the
experimental group, and the ways in which these possibilities will be accounted for. History is
certainly a significant factor, especially for a longitudinal study such as this one. For students in
Health Studies for example, a Nutrition course is required in the curriculum and so their
nutritional knowledge could be thusly increased, apart from the intervention. We plan to account
for such eventualities by including demographic questions in the questionnaires. These
questions will be of additional utility in identifying the occurrence of selection bias. For
example, if the majority of respondents to our questionnaire were female, our final conclusions
could state that the study could be generalized most accurately to women.
Attrition is another influence on validity which must be considered. Because it is a
longitudinal study, an appreciable drop-out rate is anticipated as each of the questionnaires are
administered. Fortunately, because our initial sample size is around 2000 students, even if half
the students drop out the first time (1000) and half the students drop out the second time (500),
the remaining 500 participants still constitute a reasonable sample size. The impact on validity
and our inability to correct for it, however, is acknowledged.
It is important to also consider the impact of ecological validity. Because the intervention
is being implemented in a specific University and only in one set of students (the entrance class
of 2007), ecological validity may be threatened: we may not be able to generalize our findings
and conclusions to the general population. This concern could be at least partially addressed by
conducting the study in other universities as well, and to different generations of students. This
would expand our study from just a longitudinal design to a cohort-sequential design.
Thirdly, although this study primarily aims to change healthy eating behavior, three
dependent variables are in fact assessed. This allows us to statistically analyze the relationships
between the variables, which in turn will help evaluate the effectiveness of the intervention and
suggest questions for further research. This is especially useful given that an intervention such
as this one, which makes explicit simultaneous use of all three pathways (affective, behavioral,
and cognitive), is unprecedented in the literature. For example, a result showing a high
correlation between knowledge (cognitive pathway) and behavior change but no relationship
between emotions (affective pathway) and behavior change could be the basis of a future study
intent on determining whether emotions are indeed unimportant provided that the cognitive
pathway is being activated.
We believe that our study will show that our intervention significantly improves healthy
eating behavior. The data we gather and the variables we choose to observe will facilitate future
studies exploring the complexities of the independent variable-dependent variables relationship
which will be practical and relevant.
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Appendix
[Insert Joanna’s graphs here PLUS an additional one for healthy eating behavior]
[anything else? Read through essay…]Notes

Make sure that I do the “definitions” in the Intro…

So I’ll write up the literature review as if the interventions only focused on one of three
things, and then say how ours is better because it combines multiple elements

Does Katy link her ideas to the models she discusses?

I may want to include Jacqueline’s stuff about what has been done at UW for nutrition –
but would that just make our own intervention seem cheaper by comparison?

Should probably also mention how the dependent variables will be measured

Especially the first and third…

Since I am making up the third one myself, should I talk about reliability/validity?

Do I want to make sample questions for DV #3?

Get Jacqueline/Katy to find references for the description of the intervention

Fix references

Make sure all statements in essay are supported

Check for continuity
Questions for Desmarais

How detailed do we have to describe the other studies in the literature review?

Is it OK to just organize the “Methods” section using headings?