Lecture 3 - Design DHX_MET1 Methodology 1 Stanislav Ježek Faculty of Social Studies MU •Econometrics •4. 10. 10:00--16:00 S307, •11. 10. 10:00--16:00 S307, •25. 10. 10:00--16:00 S307, •1. 11. 10:00--16:00 S307, •8. 11. 10:00--16:00 S307, •15. 11. 10:00--16:00 S307 • •Additional office hours during the above days – 14 to 15:00 @ FSS MU room 2.47 Exam •Friday December 13 •Friday January 10 • •Short open-ended items + multiple choice •Sekaran & Bougie 7th ed. • So far we have… •decided for a research question •developed a theoretical framework and specified hypotheses • • • RESEARCH DESIGN? •Research question à Research Project •Design - a strategy, plan of… •How will I find answer to my RQ? •How will I test my H? •How will I know the answer is TRUE? à VALIDITY • RESEARCH DESIGN •What are my variables (phenomena)? •What data represent my variables? •How do I get the data? •Find? •How to create data? •What will be the limitations of the data? •Representativeness •people, places, time, phenomena… •Validity – certainty about the variables affecting the data (intended, unintended) • • BASIC ELEMENTS OF RESEARCH DESIGNS - CHOICES •Gather existing data …. create data? •Precisely measure a few variables … gather rich, contextual data (many variables)? •Low interference (lurking) … high interference? •Field … laboratory? •Focus on one time …. follow the processes? •High control …. natural occurrence • • • • • • So, what is it that we want to know about designs? 1.Chose a design based on our RQ and resources 2.Specify the design so that it can produce high quality data 3.Execute the design 4.… Analyze the data • • • Types of research questions •Exploratory – we are not sure about variables •Little established theory, uncertainty about relevant variables, concepts •Focus on understanding the phenomenon in its context, on its meaning •Proposals of concepts/variables and their values (categorizations) or even theory of their relationships •Descriptive – we have questions about variables •What are variants of phenomena that occur and how frequently they occur •Correlational – are there any associations among the occurrences? •Causal – does one phenomenon give rise to another? • • Designs - templates for research – by discourse •Experimental design •experimental, quasi-experimental, single-case/small-N experimenting, ex-post-facto •Survey research •Observations •Case studies •Content/thematic analysis, Grounded theory •Action research, Evaluation research • Sekaran & Bougie think about experimental design as longitudinal. While it may appear OK, it is not. Longitudinal reserach is mostly (but not exclusively) non-experimental and basic experiments have just one measurement. Designs - templates for research – by the underlying logic •Experimental design •experimental, quasi-experimental, small-N experimenting •Non-experimental design •correlational, surveys, (longitudinal), ex-post-facto • •Qualitative designs •Case studies •Qualitative content/thematic analysis study •Grounded theory •Ethnography • • Sekaran & Bougie think about experimental design as longitudinal. While it may appear OK, it is not. Longitudinal reserach is mostly (but not exclusively) non-experimental and basic experiments have just one measurement. Ethnography •Very general theory - anthropology, sociology, psychology... •RQs how are things done around here. How are the most basic goals achieved here. •Descriptions with Focus on the meaning of behaviors. •Participant observation as the main method of data generation •Takes a long time, even years •Interference should be low due to habituation •Mostly an inspiration for flexible designs with shorter time-frames Case study •First, look at this case, then we will decide what to do next. • • exploration, description •Broadest possible range of methods to gather and create a lot of data •A lot of theory is used •Robert Yin textbooks are the best intro •Difficult generalizations • •Case: person, group, organization, program, economy… •N is often >1 Case study – practical features •Hard to hold on to your RQ •interactivity, flexibility •Potential for rich data, triangulation •Need to select case very thoughtfully •Keeping balance between observing and intervening •Beware of „success stories“! •Generalization by theory and replication. • • Content/thematic analysis Grounded theory •Theory generation - proposal •A number of cases that we compare to see what is common and what is different •Actually an analytical approach with so much theory that it becomes a design, still may be used as analytical tool within other designs •Focuses on texts and interview transcripts – less time in the field •Produces content units – topics – that may be the basis for the definition of concepts / variables and their values •GT goes on to formulate a theory of a phenomenon – what gives rize to it, what are the contextual variables that affect it and what are the consequences • Observations •What is the curent state of a phenomenon? •Do various phenomena associate (co-occur)? • •Observing the natural occurrence of variable values (phenomena) and their frequencies •May be naturalistic/unstructured …. highly structured •Minimal interference with the observed processes •You know exactly what you want to observe but it may be difficult to get access and time •Limited number of variables – good planning necessary •Descriptive RQs, correlational RQ, longitudinal RQs •Observation is used as a data generation method in other designs •Good sampling is key to representative data Surveys •What is the curent state of a phenomenon? •Do various phenomena associate (co-occur)? • •Serves the same purposes as observational research but instead of observing we ask for the observations of others •We may ask about much more than we may observe – the price is we are using untrained observers who are asked about past events – high level of uncertainty •Surprisingly high amount of expertise and theory needed to create good data •Wide range of structuring options •Huge range – we may ask about anything • Surveys – practical properties •Survey itself may be an intervention •Self-report validity •people know less than we think •the correlation between saying and doing is small •Usually a lot of variables must be measured (to achieve meaningfulness) •Useful to step back and think about existing data •We can use sophisticated statistical models to assess the fit between hypothesized associations among variables and observed data – econometrics… Experimenting – for causal RQs •If I do this, will happen what I think would happen? •What happens, will it be only beause I did this? • •manipulation with an independent variable •measurement of dependent variable, outcome •control of intervening variables Experimenting– features •Causal inference •causality generalises better than association (coincidence) •Ex is interactive, w/ strong emphasis on context •potential for further exploration, case study, qualitative work. •Ex demanding in terms of control, interference • •Ex ca be small, flexible •Ex achieves representativeness more flexibly than eg. survey •theoretical generalization and replication •Ex is demanding in terms of current knowledge • Specific applied designs •Applied, limited in generalizability, high usability •Evaluation •Action research EXPERIMENTATION IN DETAIL •We need enough theory and focus that we can identify: •Dependent variable (DV) •one or very few •measured as precisely as possible •Independent variables (IV) •one of few •manipulated so that it can create as a large effect so that we can detect it, or estimate it with sufficient precision •manipulation check – when it is not obvious we were successful in manipulating the IV •Intervening, extraneous, confounding, nuisance variables •variables associated with both DV and IV •observed(measured) •controlled – by design, statistically • • • If the hypothesis is true and everything is executed properly… •the IV will differ among perticipannt solely due to our manipulation, •IV will correlate with DV •the effects of all other variables on DV are controlled for • •Thus, if there is a reasonable theory of IV having a causal effect on DV, we can consider the correlation between IV and DV as support fora causal effect. What is control? •Making sure the intervening variable does not bias our estimate of the effect of IV on the DV •We are trying to prevent the intervening variables to correlate with IVs, DV or both •Fixing the intervening v. – make it a constant so that it cannot correlate •Randomize the IV so that it cannot correlate with the intervening variables •The intervening will still correlate with the DV but their effect will not affect the effect we want to estimate •Pairing, matching, balancing is a non random way of achieving this when IV is categorical •Measure and control statisticaly – partial/part correlation Internal validity – the concept of success •A correlation between IV and DV is considered an internally valid evidence for the causal effect of IV on DV when we can argue tha all known and unknown intervening variables have been controlled. •Then the experiment is said to be internally valid. •Can we say that the differences in DV attributed to IV are really solely due to the differences in IV? •Difficult, therefore it has the form of an argument open to discussion. •Low to high (not „is“ „is not“). • Examples of experimental designs 1.Pretest – posttest single(experimental) group •DV is measured before and after experimental manipulation is done •IV has as many values (levels) as many there are different manipulations •Within-subject design 2.Two or more group posttest only design •DV is measured after experimental manipulation has been done in each group diffrently •Experimental and control groups terminology •Each level of IV is assigned to different participants – between-subject design •Two-group pretest-posttest design •1 + 2 – add a pretest in each group of 2 – mixed design •Four-group Solomon •2 + 3 – Two groups without pretest, two with pretest • Generic threats to internal validity •History – anything that happened between pretest and posttest could have made/biased the effect •Maturation - …even the naturally running processes in our bodies, getting older, hungry, tired •Testing - …the act of pretest measurement itself could have affected the posttest or even reaction to the experiental manipulation •Selection – unbalanced groups – any known/unknown differences between the groups could have made/biased teh effect •Mortality – what if the reasons for subjects‘ leaving the study correlate with the DV? •Regression to the mean - when the groups are made according to the level of DV (or related variable). Extremes have higher probability of change towards mean. Not all experiments are true experiments •True experiments •We have full control (down to each individual) over the manipulation of the IV •Quasi-experiments •Manipulation is slightly limited by the fact that experimental groups have been formed prior to experiment. We still decide what level of IV will be assigned to each group •Informally – any experiments with obvious design weaknesses (1, 2) •Ex post facto (post hoc) studies, natural experiments •Technically not experiments but correlational studies •The IV has occurred naturally, by itself, by someone else‘s choice – we just observe it •We use the terminology and statistics of experiments (and ideály dreamof an upgrade) Field-experimenting •Issues •Randomisation •Manipulation •Ethics •Limited control •Perks •Ecological validity, generalizability •Less reactivity •Availability of people External validity - generalizability •To different participants, populations •To different settings •In teh context of lab vs. field – ecological validity. •To different times Ethics The need for control can lead us astray SUMMARY •Designs are templates for research •Most developed designs are for studies requiring most control • •For exploration with little theory – qualitative designs •For descriptive and correlational purposes – observations, surveys, ex-post-facto •For causality inference we need experiments •