NSC 260 – Overview of Research Design

Course Context

• NSC 260 lecture: “Overview of Research Design – Qualitative vs. Quantitative Research”
• Focus: how to recognise study designs, primary/secondary literature, and locate design-related information in abstracts
• Skills developed will be assessed continuously; emphasis on mastery, not rote memorisation

Learning Objectives (p. 2 & p. 24)

• Define & describe qualitative and quantitative research
• Differentiate between the two approaches
• Identify study design from an abstract (future classes will deepen this)
• Distinguish primary vs. secondary articles; classify type of secondary article
• Locate key information tied to study design in any abstract
• Recognise there is no “magic list”—requires practice & deep understanding

Primary vs. Secondary Research (general definitions)

• Primary research = authors generate original data (experiments, trials, surveys, interviews, lab work)
• Secondary research = authors analyse, synthesise or summarise existing studies (systematic reviews, meta-analyses, narrative reviews, guidelines)
• In abstracts: look for language such as “systematic review,” “meta-analysis,” “review,” “we searched,” “we identified X studies” → almost always secondary

Worked Examples of Primary/Secondary Classification

Cinnamon & Glycaemic Control (p. 3)

• Systematic review of $10$ RCTs, $n=577$
• Multiple databases searched up to Jan 2012, risk of bias assessed → Secondary article (systematic review)
• Results: mean cinnamon dose $2\,\text{g}$ daily for $4–16$ weeks; inconclusive fasting glucose effect; no HbA1c difference; mild adverse events; insufficient evidence overall

Obesity–Cancer Crosstalk (p. 4)

• Systematic review: $n=4{,}641$ articles screened → $20$ human studies included across 7 cancer types
• Mechanistic focus (VEGF, IL-6, TNFα); visceral vs. subcutaneous adipose tissue
• Secondary article (systematic review)

6-Gingerol for Chemotherapy-Induced N/V (p. 5)

• Phase II (?) RCT: $N=88$ (42 active, 46 placebo), 12-week oral 6-gingerol $10\,\text{mg}$ bid
• Primary endpoint = complete response (no emesis/rescue)
• Significant improvements: CR $77\%$ vs. 32\%\;(P<0.001); appetite $P=0.001$; FACT-G QoL higher P<0.001; less grade-3 fatigue $P=0.020$
• No toxicity → Primary quantitative clinical trial

Qualitative Research (p. 6 – p. 16)

Essence & Purpose

• Collects descriptive information: opinions, views, motivations, lived experiences
• Less structured; aims to understand “how” & “why,” formulate hypotheses rather than test them

Researcher’s Role (p. 8)

• The researcher is the “measuring instrument”
◦ Observes behaviour in natural/video settings
◦ Conducts individual/group interviews
◦ Takes detailed field notes & memos
◦ Evaluates documents/artifacts
◦ Analyses social interactions & links emerging themes/concepts
• Focus on processes rather than definitive outcomes; may uncover reasons underpinning quantitative results

Common Data-Collection Methods (p. 9)

• Narratives / in-depth interviews ⇒ family histories, personal stories
• Focus groups ⇒ interactive group discussion
• Ethnography ⇒ cultural immersion & prolonged observation

Publication Examples (p. 11)

• “Living with lymphoedema – the perspective of cancer patients”
• “The acute care experience of older persons with cognitive impairment and their families”
• “Why nutrition education is inadequate in the medical curriculum”
• “Physical and sociocultural facilitators and barriers to a nutrition program in rural Malawi”
• “Strengthening nutrition-specific policies for adolescents in Indonesia: A policy analysis”

Explaining Quantitative Findings (p. 12 & p. 13)

• Vegan vs. Western diet trial shows no inflammatory difference → follow-up interviews reveal dislike & non-compliance with vegan meals
• CVD risk-reduction program effective in university but only moderate in community → qualitative work used to identify contextual barriers (settings, resources, cultural fit)

Swartz et al. 2013 Case Study (p. 14 – p. 15)

• Focus groups ($n=20$) piloted “physical-activity-equivalent” nutrition labels (minutes/miles of walking/running needed to burn food calories)
• Iterative feedback refined gender/fitness depiction, activity type, units (miles vs. minutes)
• Key insight: labels prompted personal reflection — “How does this apply to me?” → potential behavioural advantage over standard calorie labels

Classification Rules Reminder (p. 16)

• Be able to label papers simply as “qualitative study” (primary) or “qualitative secondary” (rare, e.g., metasynthesis). No need to memorise sub-designs (phenomenology, grounded theory, etc.)

Quantitative Research (p. 17 – p. 23)

Core Features

• Relies on numerical data to measure variables in a sample population
• Enables statistical analyses & hypothesis testing

Six Common Nutrition-Science Designs (p. 20)

Experimental

1. Clinical trials (human intervention)

2. Animal studies

3. In-vitro studies (cell/tissue, test tubes, petri dishes)
   Observational

4. Cohort / Longitudinal (follow group over time)

5. Cross-sectional (snapshot epidemiology)

6. Case–control (compare diseased cases vs. healthy controls)

Evidence Hierarchy (p. 23)

• Strongest → weakest (nutrition context):
1. $\text{Randomised controlled trials}$ (human)
2. Cohort / Longitudinal studies
3. Case–control studies
4. Cross-sectional (population) studies
5. Laboratory studies (animal & in-vitro)
• Evidence pyramids often place systematic reviews/meta-analyses on top, but those are secondary analyses of primary RCTs

“Does Red Meat Cause Cancer?” (p. 19)

• Ideal (unlimited resources): large-scale, multicentre RCT randomising participants to controlled red-meat intake vs. control diet, decades of follow-up for cancer incidence → ethical & logistical constraints make this impractical; thus cohort studies are often used instead

Practice Abstract Classifications (p. 26 – p. 34)

• Cranberry & UTIs review (p. 26) → Secondary; narrative literature review with critical appraisal of clinical trials
• Carvacrol & colon-cancer cells (p. 27) → In-vitro experimental study; primary
• Food insecurity & mental health in WIHS (p. 28) → Primary quantitative cohort (prospective)
• Obesity & ASA physical status up-coding (p. 29) → Primary quantitative observational (retrospective administrative data analysis)
• Lycopene intake & prostate-cancer mortality (p. 30) → Observational quantitative cohort (prospective) primary study
• Obesity, microbiome & RA hypothesis paper (p. 31) → Secondary; narrative review/hypothesis
• Exclusive breastfeeding in The Gambia (p. 32) → Primary qualitative ethnographic study (interviews + participant observation)
• Australian university student mental health survey (p. 33) → Primary quantitative cross-sectional study (online survey)
• Army dining-facility implementation barriers (p. 34) → Primary qualitative focus-group study; explores implementation science

Recognising In-Vivo vs. In-Vitro (p. 27 Example)

• In-vitro = outside living organism (cell lines, petri dishes) → carvacrol study qualifies
• In-vivo (animal) = within living organism (rodent, etc.)

Key Numerical & Statistical Mentions

• Cinnamon review: $n=577$ over $4–16$ weeks; mean dose $2\,\text{g/day}$
• Obesity–cancer review: $n=4{,}641$ screened ⇒ $20$ clinical studies
• 6-gingerol trial: CR $77\%$ vs. $32\%$; appetite $P=0.001$; FACT-G $86.21$ vs. $72.36$; fatigue $2\%$ vs. $20\%$
• ASA coding dataset: $n=194{,}698$ patients (obesity up from $20\%$ to $39\%$, 1986-2010)

Practical Implications & Ethics

• Qualitative work respects cultural context (e.g., Gambian beliefs on water, charms, breast size)
• Quantitative RCTs require allocation concealment, blinding, consideration of adverse effects (cinnamon example lacked these)
• Secondary reviews must avoid bias via comprehensive search & transparent inclusion criteria

Study-Design Identification Strategy

• Scan for design-specific keywords ("randomized," "cohort," "cross-sectional," "focus group," "systematic review")
• Note data source: original participants/measurements vs. synthesis
• Look for time element (prospective vs. retrospective)
• Identify setting (clinical, community, laboratory, culture)
• Check outcomes: numerical endpoints → quantitative; themes/quotes → qualitative

Preparation Tips for Assessment

• Practise reading abstracts quickly—underline methods & sample descriptors
• Immediately label: primary/secondary → experimental/observational → qualitative/quantitative
• Justify classification using concrete cues (e.g., "authors conducted face-to-face interviews with 22 mothers" = qualitative primary)
• Remember the evidence pyramid to infer relative strength
• Approach material to understand reasoning, not to memorise labels only