Explaning longitudinal and cross-sectional studies with examples

1. RES EARCH M ETHODS
I N A PPLIED
LI NGUISTICSZ O L T A N D Ö R N Y E I
C H A P T E R 4
L O N G I T U D I N A L V E R S U S C R O S S - S E C T I O N A L R E S E A R C H

2. LONGITUDINAL VERSUS CROSS-
SECTIONAL RESEARCH
• Longitudinal research design can be best understood by constrasting them with
cross-sectional research design. (Menard,2002)
• In purely cross-sectional design, data are collected on one or more variables for
a single time period. (Menard, 2008)
• In longitudinal research, data are collected on one or more variables for two or
more time periods, thus allowing at least measurement of change and possibly
explaination of change. (Menard, 2008)

4. •IS IT LONGITUDINAL OR CROSS-
SECTIONAL RESEARCH?

5. Abstract
• This article reports that investigated changes in the beliefs about second language learning
of 146 trainee ESL teachers over their 3-year programme at the City University of Hong
Kong. It was hoped that while trainees might have some mistaken ideas about language
learning at the beginning of the programme, these beliefs would change as they studied
TESL methodology. I propose that it is important to work on any mistaken trainee beliefs
because they could influence their teaching and their future students' language learning for
decades. First-year trainee beliefs about language learning were collected using Horwitz's
Beliefs About Language Learning Inventory (BALLI) and compared with teacher beliefs.
Differences were found in three key areas. Developmental changes were subsequently
tracked in groups of trainees as they went through their second and third years of study.
Disturbingly, no significant changes were found (an association was also found between two
of the mismatched beliefs and ESL proficiency). An instruction package for working on
trainee beliefs was then prepared, and implemented with some success. Conclusions are that

6. Abstract
• The purpose of this study was to describe the relations among mother-child interactions as
they relate to written language, attachment security, and the child's performance on a
of emergent-literacy measures. 16 1½-year-olds, 15 3½-year-olds, and 14 5½-year-olds
participated in the study. Each mother-child dyad read through 2 books (Dribble and
Letterbook) and watched "Sesame Street" fragments about letters and words. The Strange
Situation procedure was used to observe attachment security with the youngest group. In
older groups, the children were left on their own by the mother for about 1 hour, during
they were tested and it was observed how the children reacted upon the return of the
In addition, each 3½- and 5½-year-old completed 5 emergent-literacy tests. The results
suggest that mothers of small children give reading instruction. Furthermore, it is shown that
in securely attached dyads, there is less need to discipline; the children are less distracted
in anxiously attached dyads. In addition, securely attached dyads tend to pay more attention
to reading instruction and to engage in more proto-reading. Last, children who get more
reading instruction and less narration score higher on emergent-literacy measures.

7. •WHY ARE LONGITUDINAL STUDIES
IMPORTANT FOR APPLIED
LINGUISTICS?

8. •“The simplest but incontestable is that
many questions concerning second
language learning are fundamentally
questions of time and timing”
(Ortega & Iberri – Shea, 2005, p. 27)

9. MANY BROADER SLA QUESTIONS THAT
REQUIRE ANSWERS MUSTERED IN
LONGITUDINAL EVIDENCE.
• WHAT DO WE KNOW ABOUT THE PACE AND PATTERNS OF DEVELOPMENT IN
SECOND LANGUAGE AND LITERACY, THROUGHOUT THE LIFETIME OF L2 LEARNERS?
• WHAT CRITICAL TRANSITION POINTS IN L2 DEVELOPMENT NEED TO BE TAKEN INTO
ACCOUNT WHEN PLANNING AND EVALUATING EDUCATIONAL POLICY AND
PRACTICE FOR SPECIFIC L2 LEARNER POPULATIONS?
(Ortega & Iberri – Shea, 2005, p.
28)

10. DEFINITION OF LONGITUDINAL
RESEARCH
• Collected data for two or more distinct time periods
• Same or comparable analysed cases from one period to the
next
• Analysis involving some comparison of data between periods

11. LONGITUDINAL RESEARCH SERVES
TWO PRIMARY PURPOSES
• To describe patterns of change and to establish the direction
(positive or negative and from Y to X or from X to Y)
• To describe magnitude of causal relationship.
(Menard, 2002, p.2)

12. LONGITUDINAL RESEARCH IS RATHER
UNDERUTILIZED IN OUR FIELD
•Smallar data collection points when compared
with other fields like economics
•Traditionally associated with quantitative
paradigms

13. MAIN TYPES OF LONGITUDINAL
RESEARCH
•Prospective longitudinal studies or panel
studies
•Repeated cross-sectional studies or trend
studies
•Retrospective longitudinal studies
•Simultaneous cross-sectional studies

14. PROSPECTIVE LONGITUDINAL
STUDIES OR PANEL STUDIES
• Panel studies are a particular design of longitudinal
study in which the unit of analysis is followed at
specified intervals over a long period, often many
years. The key feature of panel studies is that they
collect repeated measures from the same sample at
different points in time. (Laurie, 2013)

15. PROSPECTIVE LONGITUDINAL
STUDIES OR PANEL STUDIES
• Follow-up study, Cohort study
• Possibility to collect information about change at the
micro level as it really happens
• Powerful nonexperimental method for examining
development and causality

16. PROSPECTIVE LONGITUDINAL STUDIES
OR PANEL STUDIES-THREATS TO THEIR
VALIDITY AND CONS OF STUDIES
Cons of Panel Studies Threats to Validity
• Expensive
• Time consuming
• Committed research team
• Attrition
• Panel conditioning

17. PANEL CONDITIONING
• That the act of measurement can alter that which is being
measured.
A psychological research on panel conditioning
Randomly assigned newlywed couples to one of two groups: one that
participated in frequent and intensive interviews (the “study group”)
marital satisfaction and well-being over the course of four years and
that participated in minimal and infrequent interviews over that period.
authors concluded that “ by the fourth year … the marriages of the study
group couples appeared to be better adjusted on several dimensions of
marital quality” Those randomly assigned to reflect on the quality of
relationships subsequently had different attitudes about those
than members of a control group.
(Halpern-Manners & Warren, 2012)

18. • Method: Five children (3 boys, 2 girls) were identified as late talkers
and divided into a younger group and an older group. Each child was
followed monthly for 10 to 12 months (22–33 months for the younger
group and 30–42 months for the older group). Two types of monthly
language samples (free play and elicited) were obtained to describe
individual courses of phonological development for each child.
Independent and relational analyses were completed at each age to
describe word-initial and word-final phonetic inventories, syllable
structure, syllable diversity, percentage of consonants correct (PCC),
sound variability, and error patterns.

19. REPEATED CROSS-SECTIONAL STUDIES
OR TREND STUDIES
• Repeated cross-sectional data are created where a
survey is administered a new sample of interviewees
at successive time points. For an annual survey, this
means that respondents in one year will be different
people to those in a prior year. (UK Data Service, 2015)

20. REPEATED CROSS-SECTIONAL STUDIES
OR TREND STUDIES- ADVANTAGES OVER
PANEL STUDIES
PROS CONS
• Cheaper to conduct
• Easier to arrange
• No attrition
• No panel conditioning
• Not suited to resolve issues of
causal order
• Not suited to study
developmental patterns
• The need to use the same
questionnaire

21. • Method: All health care workers from a public health care facility
were invited to complete a questionnaire containing questions on
workplace violence. Three questionnaire-based cross-sectional
surveys were conducted. The response rate was 75 % in 2005, 71
in 2007, and 94 % in 2009. The 2009 questionnaire contained the
VIF (Violent Incident Form) for reporting violent incidents, the
(demand/control/support) model for job strain, the Colquitt 20
item questionnaire for perceived organizational justice, and the
GHQ-12 General Health Questionnaire for the assessment of
mental health.

22. RETROSPECTIVE LONGITUDINAL
STUDIES
• Retrospective longitudinal data are gathered during a single
investigation in which respondents are asked to think back
and answer questions about the past.
PROS CONS
• Time-saving
• Economic
• Unreliable data from
participants

23. Abstract
This article examines the relationship between political change and university
students' sense of identity in South Africa during a 10-year period. Prior to
identity in South Africa was largely based on ethnicity and language; is this still
the case today? The new government has not only forced people to face
changes in political issues but also changes in identification issues. Nowhere are
these issues more striking than in an institution of higher learning, where
students from diverse ethnic backgrounds are unified by a similar goal—an
education. In an attempt to address the issue of identification, a survey was
conducted at Rand Afrikaans University in Johannesburg, South Africa, to
determine if the change in government is causing a change in how people
perceive themselves.

24. SIMULTANEOUS CROSS-SECTIONAL
STUDIES
• Simultaneous cross-sectional studies are conducted with
different age groups sampled, only partially longitudinal,
because it does not involve the examination of change over
time but rather across age groups.
• Respondants’ age is the key sampling variable, while in
ordinary cross-sectional designs age is just another variable.

25. SIMULTANEOUS CROSS-SECTIONAL
STUDIES
PROS CONS
• Straightforward
• Economical
• Cohort effects
• Having to devise generic
items

26. COHORT EFFECTS
• Who is a cohort?
• What do you think the results are?
Think about how different a group of American children
who grew up in the Great Depression would be from
children who grew up in the prosperous 1990s. An
example of a cohort effect could be seen in an
experiment in which participants use a computer to
perform a cognitive task.

27. COHORT EFFECTS
The results:
Participants in their 20s did better on the cognitive test that
participants in their 60s. But a cohort effect is responsible for the
significance- the participants in their 20s have been using computers
their entire lives and were more comfortable and proficient with the
computerized testing format than the participants in their 60s.
The influence that a person’s date and place of
birth has on social research is known as

28. Abstract
Made simultaneous cross-sectional and longitudinal comparisons of WAIS
performances of 70 Ss. The comparisons were such that approximately 4 years
separated the age groups both cross-sectionally and longitudinally. The groups
were aged 60–63, 64–67, 68–71, and 72–75 years. The results indicate no significant
age differences with the cross-sectional comparison but significant age differences
with the longitudinal comparisons. The latter differences, however, were small. It is
concluded that when the age spans of cross-sectional and longitudinal comparisons
are equivalent and when equivalent S selection factors are applied to these 2
designs, the results are similar.

29. OTHER LONGITUDINAL DESIGNS –
INDIGENIOUS WAYS TO REMEDY SOME OF
THE WEAKNESSES
• Rotating panels
• Split panels
• Linked or administrative panels
• Cohort study
• Accelatered longitudinal design
• Experimental research
• Interrupted time-series design
• Diary studies

30. LONGITUDINAL QUALITATIVE
RESEARCH
• Devising longitudinal Qual studies is relatively easy;
replacement of the Quan data collection with Qual
method.
• Cross-sectional representativeness is unlikely to be
achieved.
• Qual Panel or Retrospective studies are straightforward
to devise.

31. LONGITUDINAL QUALITATIVE
RESEARCH
•WHY HAVE THERE BEEN SO FEW
LONGITUDINAL QUAL
INVESTIGATIONS?

32. LONGITUDINAL QUALITATIVE RESEARCH –
TWO DETERRENTS OF THE DESIGN
LABOUR-INTENSIVE DATA ANALYSIS INCREASED PANEL CONDITIONING
1. Interviews
2. Individual narrative analysis
3. Summary narrative analysis
4. Producing a case profile for each
participant
5. Tracing changes in narratives
over time
6. Final interpretations from
synthesis of data
• Researcher and respondent are
journeying together, which is a
serious threat to validity.

33. LONGITUDINAL MIXED DESIGNS
• The QUAL and QUAN traditions of longitudinal
research are complementary.
• Longitudinal studies are inherently concerned both
with the micro and macro level of development and
change, the mixing of approaches is theoretically
warranted.

34. CHOOSING A DESIGN: LONGITUDINAL
OR CROSS-SECTIONAL?
• NOBODY CAN BE BLAMED FOR TAKING THE EASIER
WAY OUT AND CONDUCTING A CROSS-SECTIONAL
STUDY.

35. WHEN IS IT MORE APPROPRIATE TO USE
LONGITUDINAL THAN A CROSS-
SECTIONAL DESIGN?
• Longitudinal studies is suitable for dynamic elements.
• Cross-sectional research is useful to describe variables
and patterns of relationships at a particular time.
• There is little or nothing that cross-sectional research
can do that longitudinal research cannot.

36. QUANTITATIVE LONGITUDINAL DATA
ANALYSIS
• The main deterrent of QUAN longitudinal research:
the complexity of the data analysis
• Change can happen in very different forms
• There is no generic statistical procedure for analysing

37. REFERENCES
Botwinick, J., & Siegler, I. (1980). Intellectual ability among the elderly: Simultaneous cross-sectional and longitudinal
comparisons. Developmental Psychology, 16(1), 49-53.
Bus, A., & van IJzendoorn, M. (1988). Mother-Child Interactions, Attachment, and Emergent Literacy: A Cross-Sectional Study. Child
Development, 59(5), 1262.
Dörnyei, Z. (2007). Research methods in applied linguistics: Quantitative, qualitative, and mixed methodologies. Oxford: Oxford University Press.
Goldschmidt, M. (2003). Identifying Labels among University Students in the New South Africa. Journal Of Black Studies, 34(2), 204-221.
Halpern-Manners, A., & Warren, J. (2012). Panel Conditioning in Longitudinal Studies: Evidence From Labor Force Items in the Current
Population Survey. Demography, 49(4), 1499-1519.
Laurie, H. (2013). Panel Studies. Oxford Bibliographies Online Datasets.
Magnavita, N., & Heponiemi, T. (2012). Violence towards health care workers in a Public Health Care Facility in Italy: a repeated cross-sectional
study. BMC Health Services Research, 12(1).

38. REFERENCES
Menard, S. (2002) Longitudinal Research, 2nd Edition. Thousand Oaks, Calif.: Sage.
Menard, S. (2008). Handbook of longitudinal research. Amsterdam: Elsevier.
Ortega, L., & Iberri-Shea, G. (2005). LONGITUDINAL RESEARCH IN SECOND LANGUAGE ACQUISITION: RECENT TRENDS
AND FUTURE DIRECTIONS. Annual Review Of Applied Linguistics, 25.
Peacock, M. (2001). Pre-service ESL teachers' beliefs about second language learning: a longitudinal study. System, 29(2), 177-195.
Psychology Glossary. Psychology definitions in plain English.. (2017). Alleydog.com. Retrieved 28 September 2017, from
http://www.alleydog.com/glossary/
Rafferty, A., Walthery, P., & King-Heşe, S. (2015) Analysing change over time: repeated cross-sectional and longitudinal survey data. UK
Data Service, University of Essex and University of Manchester.
Williams, A., & Elbert, M. (2003). A Prospective Longitudinal Study of Phonological Development in Late Talkers. Language Speech And
Hearing Services In Schools, 34(2), 138.