How to Write an Abstract for Your Thesis or Dissertation
What is an Abstract?
- The abstract is an important component of your thesis. Presented at the beginning of the thesis, it is likely the first substantive description of your work read by an external examiner. You should view it as an opportunity to set accurate expectations.
- The abstract is a summary of the whole thesis. It presents all the major elements of your work in a highly condensed form.
- An abstract often functions, together with the thesis title, as a stand-alone text. Abstracts appear, absent the full text of the thesis, in bibliographic indexes such as PsycInfo. They may also be presented in announcements of the thesis examination. Most readers who encounter your abstract in a bibliographic database or receive an email announcing your research presentation will never retrieve the full text or attend the presentation.
- An abstract is not merely an introduction in the sense of a preface, preamble, or advance organizer that prepares the reader for the thesis. In addition to that function, it must be capable of substituting for the whole thesis when there is insufficient time and space for the full text.
Size and Structure
Clearly Specify Your Research Questions
- Currently, the maximum sizes for abstracts submitted to Canada's National Archive are 150 words (Masters thesis) and 350 words (Doctoral dissertation).
- To preserve visual coherence, you may wish to limit the abstract for your doctoral dissertation to one double-spaced page, about 280 words.
- The structure of the abstract should mirror the structure of the whole thesis, and should represent all its major elements.
- For example, if your thesis has five chapters (introduction, literature review, methodology, results, conclusion), there should be one or more sentences assigned to summarize each chapter.
- As in the thesis itself, your research questions are critical in ensuring that the abstract is coherent and logically structured. They form the skeleton to which other elements adhere.
- They should be presented near the beginning of the abstract.
- There is only room for one to three questions. If there are more than three major research questions in your thesis, you should consider restructuring them by reducing some to subsidiary status.
Don't Forget the Results
- The most common error in abstracts is failure to present results.
- The primary function of your thesis (and by extension your abstract) is not to tell readers what you did, it is to tell them what you discovered. Other information, such as the account of your research methods, is needed mainly to back the claims you make about your results.
- Approximately the last half of the abstract should be dedicated to summarizing and interpreting your results.
© John C. Nesbit
Electronic cigarette (e-cigarette) use is increasing rapidly, and the impact on youth is unknown. We assessed associations between e-cigarette use and smoking intentions among US youth who had never smoked conventional cigarettes.
We analyzed data from the nationally representative 2011, 2012, and 2013 National Youth Tobacco Surveys of students in grades 6–12. Youth reporting they would definitely not smoke in the next year or if offered a cigarette by a friend were defined as not having an intention to smoke; all others were classified as having positive intention to smoke conventional cigarettes. Demographics, pro-tobacco advertisement exposure, ever use of e-cigarettes, and ever use of other combustibles (cigars, hookah, bidis, kreteks, and pipes) and noncombustibles (chewing tobacco, snuff, dip, snus, and dissolvables) were included in multivariate analyses that assessed associations with smoking intentions among never-cigarette-smoking youth.
Between 2011 and 2013, the number of never-smoking youth who used e-cigarettes increased 3-fold, from 79,000 to more than 263,000. Intention to smoke conventional cigarettes was 43.9% among ever e-cigarette users and 21.5% among never users. Ever e-cigarette users had higher adjusted odds for having smoking intentions than never users (adjusted odds ratio = 1.70, 95% confidence interval = 1.24–2.32). Those who ever used other combustibles, ever used noncombustibles, or reported pro-tobacco advertisement exposure also had increased odds for smoking intentions.
In 2013, more than a quarter million never-smoking youth used e-cigarettes. E-cigarette use is associated with increased intentions to smoke cigarettes, and enhanced prevention efforts for youth are important for all forms of tobacco, including e-cigarettes.
The impact of new and emerging products, including electronic cigarettes (e-cigarettes) and other electronic nicotine delivery systems (ENDS),1 on youth use of conventional combusted tobacco products is unknown2,3 Surveillance data on ENDS use and related behaviors remain scarce, and there is much speculation about the net public health impact of ENDS at the population level.3–5 ENDS are being marketed heavily, using both traditional (e.g. television) and digital marketing strategies.6–10 ENDS use is increasing rapidly among both adults and youth11–13 with ever e-cigarette use doubling from 3.3% to 6.8% between 2011 and 2012 among middle and high school students.11
Preventing youth initiation and transition to established smoking are critical and well-established public health goals.14,15 Cigarette smoking remains the leading cause of preventable disease and death in the United States, and more than 80% of adult smokers begin smoking by 18 years of age.16 While cigarette smoking rates have declined in recent decades in the United States, an estimated 5.6 million American children alive today will die prematurely from a smoking-related illness unless smoking rates decline much more.15 Evidence-based strategies, including mass media campaigns, price increases, and changes in smoke-free policies and norms have been effective in reducing the initiation, prevalence, and intensity of youth smoking in settings where they have been comprehensively implemented.16,17 Full implementation of comprehensive tobacco control programs, coupled with FDA regulation of tobacco products,18 would be expected to reduce youth tobacco use further. However, implementation has been limited and uneven across states and communities, and an estimated 3000 youth start smoking cigarettes every day.16
The use of cigarettes and other combusted tobacco products has been the principle cause of the 20 million tobacco-related deaths that have occurred in the United States since 1964.15 In theory, if ENDS (including e-cigarettes) or other nicotine delivery devices cause less harm than cigarettes and other combustible tobacco products, their use by current conventional tobacco smokers could reduce disease and death, if smokers switch completely and end all combustible product use.19 ENDS are more likely to be beneficial if their use is concurrent with interventions that rapidly reduce the appeal, accessibility, promotion, and use of cigarettes.15 However, if conventional tobacco smokers become concurrent users of ENDS and combustible products (dual users) rather than quitting both products or completely substituting ENDS for combustible products, or if ENDS leads to initiation of nicotine use among nonusers and relapse among former smokers, then ENDS could result in net public health harm to the US population.15 ENDS, which contain nicotine, may be particularly harmful to youth, because ENDS and nicotine exposure could have long-term negative consequences on adolescent brain development,15 can result in nicotine addiction,20 and have the potential to lead youth to use other forms of tobacco products.2
Prior research has examined youth experimentation and progression to cigarette smoking.15 Measures of intention to smoke cigarettes have been validated21 and have been shown to predict future cigarette smoking, irrespective of previous smoking behavior.22,23 Additionally, research has identified other predictors of future cigarette use, including exposure to pro-tobacco marketing and promotion, living with a smoker, parental smoking, having friends who smoke, and performing poorly in school.24–26 However, additional research will be useful to understand predictors of intention to use cigarettes, given the changing tobacco product landscape with the advent of ENDS.
To address this gap and to help inform decisions regarding public health policy and practice, we analyzed US nationally representative data from the 2011, 2012, and 2013 National Youth Tobacco Surveys (NYTS) to determine if e-cigarette use is associated with elevated intentions to smoke conventional cigarettes among middle and high school students who have never smoked cigarettes.
The NYTS is a nationally representative, self-administered survey of US students enrolled in grades 6–12 in both public and private schools. Details of the NYTS methodology are available elsewhere (http://www.cdc.gov/TOBACCO/data_statistics/surveys/NYTS/index.htm). In brief, NYTS uses a stratified, three-stage cluster sample design to produce a nationally representative sample of middle school and high school students in the US Sampling procedures are probabilistic and conducted without replacement at all stages, and entail selection of Primary Sampling Units (PSUs) within each stratum, schools within each selected PSU, and, lastly, classes within each selected school. Participation is voluntary for schools and students and anonymous at the student level. Participants complete the self-administered, scannable questionnaire booklet via pencil and paper.
We analyzed data from the 2011, 2012, and 2013 NYTS. Overall NYTS participation rates, representing the product of the school-level and student-level participation rates, were 67.8% in 2013 with 18,406 completed student questionnaires, 73.6% in 2012, with 24,658 completed student questionnaires, and 72.7% in 2011, with 18,866 completed student questionnaires.
For all of the definitions below, specific questionnaire wording is available at (http://www.cdc.gov/TOBACCO/data_statistics/surveys/NYTS/index.htm).
Never Cigarette Smokers
Students who selected “no” to the question “Have you ever tried cigarette smoking, even one or two puffs?” were considered never cigarette smokers. Those who selected “yes” were considered ever cigarette smokers.
Intention to Use Cigarettes Among Never Cigarette Smokers
Drawing from prior research,21–23 we defined intention to use cigarettes among never cigarette smokers as lacking a firm commitment not to smoke, using a composite measure of the two questions that were available for all three survey years: “Do you think you will smoke a cigarette in the next year?” and “If one of your best friends were to offer you a cigarette, would you smoke it?” Response options included: “definitely yes,” “probably yes,” “probably not,” and “definitely not.” Those who responded “definitely not” to both intentions questions were classified as not having intentions; otherwise, respondents were classified as having intentions. This definition was also applied to 0.45% of the total sample who had a missing response to one of the two intentions questions and were classified as having intentions. Respondents with missing responses to both intentions questions represented 0.35% of the sample and were excluded. In addition, we conducted analyses using two alternative definitions. One used only a single question (smoking in the next year) to define intentions and the second only classified respondents as having intentions if they responded “definitely yes” or “probably yes” to the two intentions questions.
Ever Electronic Cigarette Users
Students who selected “Electronic Cigarettes or E-cigarettes, such as Ruyan or NJOY” to the question “Which of the following products have you ever tried, even just one time?” were considered ever e-cigarette users.
Current Electronic Cigarette Users
Students who selected “Electronic Cigarettes or E-cigarettes, such as Ruyan or NJOY” to the question “In the past 30 days, which of the following products have you used on at least one day?” were considered to be current e-cigarette users.
Ever Other Combustible User
Other combustible tobacco products assessed included: cigars, hookah, bidis, kreteks, and pipes. Students who reported ever use of any of these other combustible products were considered to be ever other combustible product users.
Current Other Combustible User
Students who reported using any of the other combustible products on at least one day in the last 30 days were defined as current other combustible users.
Ever Noncombustible Users
Noncombustible products included chewing tobacco, snuff, dip, snus, and dissolvables. Students who reported ever use of any of these noncombustible products were defined as ever noncombustible users.
Current Noncombustible Users
Students who reported using any of the noncombustible products on at least one day in the last 30 days were defined as current noncombustible users.
Pro-tobacco advertisement exposures were assessed for the following media sources: internet, magazine/newspaper, retail, and television/movies. For each source, respondents were asked “…how often do you see ads or promotions for cigarettes or other tobacco products?,” with the beginning of the question describing each particular media source. Respondents who answered “I do not use/read/go/watch,” “never,” or “rarely” were considered not exposed to that source; otherwise, those who answered that they had seen pro-tobacco advertisements “sometimes,” “most of the time,” or “always” were considered exposed to pro-tobacco advertisement through that source. The total number of distinct sources of pro-tobacco advertisement exposure reported by each student was summed to create a cumulative exposure measure and categorized (none, 1–2, 3–4).
Student characteristics included: sex (male or female), school level (middle or high), presence of a tobacco user in the household (yes or no), and race/ethnicity (non-Hispanic white, non-Hispanic black, non-Hispanic other, or Hispanic). The ‘non-Hispanic other’ category included respondents who were non-Hispanic and Asian, Native American or Alaska Native, Hawaiian or Pacific Islander, or multiple races. Additionally, survey year (2011, 2012, or 2013) was assessed.
Household Member Uses Tobacco
Students who responded and selected anything other than “no one who lives with me now uses any form of tobacco” to the question “Does anyone who lives with you now…?” were considered to live with a household member that uses tobacco.
Students who reported being in 6th, 7th, or 8th grades were considered to be in middle school. Those who reported being in 9th, 10th, 11th, or 12th grades were considered to be in high school.
To augment sample size of ever and current electronic cigarette users who had never smoked cigarettes for the intention to smoke analysis, we pooled data from the 2011, 2012, and 2013 NYTS surveys. Data were adjusted for nonresponse and weighted to be representative of the US middle and high school student population; 95% confidence intervals (CIs) were calculated to account for the complex survey design. All analyses were performed using SAS-Callable SUDAAN (v. 11.0.0).
We assessed respondent characteristics and prevalence of ever and current use of e-cigarette use among never cigarette smokers (n = 43,873). Characteristics and exposures were assessed for never smokers with and without smoking intentions. Chi-squared tests were used to compare differences across these two groups. Multivariate logistic regression models were fit for never cigarette smokers to assess correlates of intention to smoke (p < .05). Different models were used to assess current and ever use of e-cigarettes. Covariates included sex, race/ethnicity, school level, number of distinct sources of pro-tobacco advertisement exposure, presence of a tobacco user in the household, and survey year. Variables for ever and current other combustible use and noncombustible use were included in the ever and current models, respectively. In addition, we fit models with categorical (ever use, current use, and never use) variables for combustible, noncombustible and e-cigarette use and models using two other definitions for smoking intentions. One definition only classified respondents as having intentions if they responded “definitely yes” or “probably yes” to the two intentions questions and the other used only a single question to define intentions (i.e. smoking in the next year). For all models, variables were entered into the model simultaneously and no model reduction procedures were performed.
Overall, 73.0% (95% CI = 71.6–74.3) of youth (n = 43,873) were never cigarette smokers. Of all youth, 6.1% (95% CI = 5.5–6.6) reported ever e-cigarette use, including 20.2% (95% CI = 18.7–21.8) among ever cigarette smokers and 0.9% (95% CI = 0.7–1.1) among never cigarette smokers. Current e-cigarette use was 6.9% (95% CI = 6.2–7.8) among ever cigarette smokers and 0.3% (95% CI = 0.2–0.4) among never cigarette smokers. From 2011 to 2013, weighted population estimates among students who were never cigarette smokers but had ever used an e-cigarette increased over 3-fold, from approximately 79,000 (95% CI = 44,000–114,000) to over 263,000 (95% CI = 176,000–351,000).
Intention to Smoke Cigarettes
Overall, 21.9% (95% CI = 21.2–22.6) of never cigarette smokers had smoking intentions. Smoking intention was 43.9% (95% CI = 37.1–50.9) among ever e-cigarette users compared with 21.5% (95% CI = 20.9–22.2) among those who had never tried e-cigarettes (p < .001).
Prevalence of smoking intention varied by demographic and tobacco use characteristics among never cigarette smokers (Table 1). Intention to smoke was highest among Hispanic students (27.5%) compared with other race/ethnicity groups (p < .001). Intention to smoke was 26.7% (95% CI = 25.5–27.9) among those who lived with a tobacco-using household member compared with 19.4% (95% CI = 18.6–20.2) among those who did not (Table 1).
Smoking Intention and Characteristics of Middle and High School Students Who Were Never Smokers: National Youth Tobacco Survey, 2011–2013
|Characteristics and exposures||Never smoker (n = 43,873)||Never smoker, no smoking intention (n = 33,951)||Never smoker, smoking intention (n = 9,897)||Chi-squared test p|
|% (95% CI)||% (95% CI)||% (95% CI)|
|Smoking intention||Yes||21.9 (21.2–22.6)||—||—||—|
|Year||2011||32.4 (28.2–36.9)||77.2 (75.8–78.5)||22.8 (21.5–24.2)||<.001|
|2012||33.7 (30.1–37.4)||75.0 (74.1–75.9)||25.0 (24.1–25.9)|
|2013||33.9 (30.1–37.9)||82.1 (81.1–83.2)||17.9 (16.8–18.9)|
|Sex||Female||50.4 (49.6–51.1)||78.4 (77.5–79.4)||21.6 (20.6–22.5)||.255|
|Male||49.6 (48.9–50.4)||77.8 (77.0–78.6)||22.2 (21.4–23.0)|
|School||Middle||51.2 (48.2–54.2)||78.7 (77.8–79.6)||21.3 (20.4–22.2)||.054|
|High||48.8 (45.8–51.8)||77.4 (76.3–78.5)||22.6 (21.5–23.7)|
|Race/ethnicity||Non-Hispanic White||55.4 (52.4–58.3)||79.4 (78.5–80.3)||20.6 (19.7–21.5)||<.001|
|Non-Hispanic Black||14.2 (12.4–16.3)||80.3 (78.5–81.9)||19.7 (18.1–21.5)|
|Hispanic||19.6 (17.8–21.5)||72.5 (71.1–73.9)||27.5 (26.1–28.9)|
|Non-Hispanic other||10.8 (9.8–11.9)||79.0 (77.1–80.7)||21.0 (19.3–22.9)|
|Internet ads||Yes||40.5 (39.6–41.3)||73.7 (72.7–74.7)||26.3 (25.3–27.3)||<.001|
|No||59.5 (58.7–60.4)||81.2 (80.4–81.9)||18.8 (18.1–19.6)|
|Magazine/newspaper ads||Yes||37.0 (36.1–37.8)||74.6 (73.5–75.6)||25.4 (24.4–26.5)||<.001|
|No||63.0 (62.2–63.9)||80.2 (79.4–81.0)||19.8 (19.0–20.6)|
|Retail ads||Yes||76.9 (76.0–77.8)||76.7 (75.9–77.5)||23.3 (22.5–24.1)||<.001|
|No||23.1 (22.2–24.0)||82.9 (81.9–84.0)||17.1 (16.0–18.1)|
|Television program/movie ads||Yes||69.2 (68.3–70.0)||76.7 (75.9–77.4)||23.3 (22.6–24.1)||<.001|
|No||30.8 (30.0–31.7)||81.5 (80.4–82.6)||18.5 (17.4–19.6)|
|Total number of distinct sources of pro-tobacco advertisements exposed to||None||10.0 (9.5–10.5)||87.0 (85.5–88.3)||13.0 (11.7–14.5)||<.001|
|1–2||47.8 (47.1–48.6)||79.6 (78.8–80.5)||20.4 (19.5–21.2)|
|3–4||42.2 (41.4–43.0)||74.4 (73.4–75.3)||25.6 (24.7–26.6)|
|Household member uses tobacco||Yes||34.3 (33.0–35.7)||73.3 (72.1–74.5)||26.7 (25.5–27.9)||<.001|
|No||65.7 (64.3–67.0)||80.6 (79.8–81.4)||19.4 (18.6–20.2)|
|Ever use of e-cigarettes||Yes||0.9 (0.7–1.1)||56.1 (49.1–62.9)||43.9 (37.1–50.9)|
|No||99.1 (98.9–99.3)||78.5 (77.8–79.4)||21.5 (20.9–22.2)|
|Other combustible tobacco products||Yes||7.7 (7.1–8.2)||61.7 (59.5–63.8)||38.3 (36.2–40.5)||<.001|
|No||92.3 (91.8–92.9)||79.5 (78.8–80.2)||20.5 (19.8–21.2)|
|Other noncombustible tobacco products||Yes||3.0 (2.6–3.3)||58.6 (55.7–61.5)||41.4 (38.5–44.3)||<.001|
|No||97.0 (96.7–97.4)||78.7 (78.0–79.4)||21.3 (20.6–22.0)|
|Current (past 30 days) use:e-cigarettes||Yes||0.3 (0.2–0.4)||58.2 (47.5–68.1)||41.8 (31.9–52.5)|
|No||99.7 (99.6–99.8)||78.3 (77.6–79.0)||21.7 (21.0–22.4)|
|Other combustible tobacco products||Yes||2.6 (2.4–2.9)||60.4 (56.4–64.3)||39.6 (35.7–43.6)||<.001|
|No||97.4 (97.1–97.6)||78.6 (77.9–79.3)||21.4 (20.7–22.1)|
|Other noncombustible tobacco products||Yes||1.0 (0.9–1.2)||59.3 (54.1–64.3)||40.7 (35.7–45.9)|