社会的研究方法双语教学课件-专业-.ppt

1、lWhat is social research?Way of knowing social reality by direct experiencelDefinitionlThe differences between“social research”and“社会调查研究“lDescription(描述)A major purpose of many social scientific studies is to describe situations and events.The researcher observes and then describes what was observe

2、d.Since scientific observations is careful and deliberate,however,scientific descriptions are typically more accurate and precise than casual descriptions.(P73)Examples l北京汽车市场调查 农村居民收入差距lThe second general purposes of social scientific research is to explain things.Reporting the voting intentions o

3、f an electorate is a descriptive activity,but reporting why some people plan to vote for candidate A and others for candidate B is an explanatory activity.Reporting why some cities have higher crime rates than others is a case of explanation,but simply reporting the different crime rates is a case o

4、f description.lFor example,the goal of regression analysis is find out the relationship between two or more variables.lObjetctive dimensionA.Census(普查).lAn enumeration(列举)of the characteristics of some population(总体).A census is often similar to a survey,with the difference that the census collects

5、data from all members of the population while the survey is limited to a sample.B.lCareful probability sampling provides a group of respondents whose characteristics may be taken to reflect those of the larger population,and carefully constructed standardized questionnaires provide data in the same

6、form from all respondents.lTake only several members from the population and study them in detail.descriptive studies(描述性研究)explanatory studies(解释性研究)lCross-sectional Study(横剖研究).A study that is based on observations representing a single point in time.lLongitudinal Study（纵贯研究）.A study design involv

7、ing the collection of data at different points in time,as contrasted with a cross-sectional study.lLongitudinal studies are designed to permit observations over an extended period.Three types of longitudinal studies should be noted here.lTrend studies(趋势研究)are those that study changes within some ge

8、neral population over time.Examples would be a comparison of U.S.Census over time,showing growth in the national population,or a series of Gallup Polls during the course of an election campaign,showing trends in the relative strengths and standing of different candidates.lCohort Studies(同期群研究)examin

9、e more specific subpopulations(cohorts)as they change over time.Typically,a cohort is an age group,such as those people born during the 1920s,but it can also be based on some other time grouping,such as people attending college during the Vietnam War,people who got married in 1964,and so forth.lAn e

10、xample of cohort study would be a series of national surveys,conducted perhaps every 10 years,to study the economic attitudes of the cohort born during the depression of the early 1930s.a sample of persons 20-25 years of age might be surveyed in 1960,and another sample of those 40-45 years of age in

11、 1970.Although the specific set of people studied in each of those surveys would be different,each sample would represent the survivors of the cohort born between 1930 and 1935.lPanel Studies(定组研究定组研究,追踪研究追踪研究)are similar to trend and cohort studies except that the same set of people is studied each

12、 time.One example would be a voting study in which the same sample of voters was interviewed every month during an election campaign and asked for whom they would intended to vote.Such a study would make it possible to analyze overall trends in voter preferences for different candidates,but it would

13、 have the added advantage of showing the precise patterns of persistence and change in intentions.lFor example,a trend study that showed that Candidates A and B each had exactly half of the voters on September first and on October first as well could indicate that none of the electorate had changed

14、voting plans,that all of the voters had changed their intentions,or something between.A panel study would eliminate this confusion by showing what kinds of voters switched from A to B and what kinds switched from B to A,as well as other facts.lPreparatory stage(准备阶段)lData collection stage(收集资料阶段)lAn

15、alysis stage(分析阶段)lSummary stage(总结阶段)l1.Choose a research projecta)How to choose a research projectl b)Factors relating with research project choicec)Principles regarding research project choicel2.Preliminary Exploration l a)Literature reviewl b)Filed observation l3.Research Project Design a)Resear

16、ch hypothesisb)Research planl1.Purposes of Literature ReviewTo avoid redundant research and try to make new contributionsTo provide bases for hypothesis To take other researches as references for your research planl2.How to Review Literature Snowball method:according to the references and notes of t

17、he existing literature to look for more related literatureElectronic resourceslMethods:colloquia(座谈会）,interview,refer to literaturelPurpose1:for questionnaire designlExample:how to measure peasant family income into three levels:“high”,“medium”and“low”lPurpose 2:for hypothesislExample:Economicdevelo

18、pmentImplementation of electoral systemVillagersparticipationl3.1 Research HypothesisHypothesis:An expectation about the nature of things derived from a theory.Functions of hypothesis:lTo guild a researchlTo relate theoretical concepts with empirical datalTo explore new theoretical knowledgePrincipl

19、es for making hypothesislConsistent with existing theorieslConsistent with confirmed factslCan be verified by experiencelPurposeslPopulation and objectslSampling methodslMethods of data collection and data analysislOrganizationlBudget and facilitieslWages,travelling expenses,expense for copying and

20、printinglFacilities:camera,tape recorder,computerlTimetablel3.1 Introduction to Samplingl1.The history of samplingl2.Sampling concepts and terminologyl3.2 Probability Sampling(随机抽样）l1.Simple random sampling(SRS)简单随机抽样l2.Systematic sampling 系统抽样l3.Stratified sampling 分层抽样l4.Cluster sampling 整群抽样l5.Mu

21、lti-stage sampling 多段抽样l3.3 Non-Probability Sampling（非随机抽样）l1.Purposive or judgment sampling 立意抽样l2.Quota sampling 配额抽样l3.Snowball sampling 滚雪球抽样l1.The history of samplingPolitical polling by Literacy Digest In 1920,Digest editors mailed postcards to people in six states,asking them who they were pl

22、anning to vote for in the presidential campaign between Warren Harding and James Cox.Names were selected for the poll from telephone directories and automobile registration lists.Based on the postcards sent back,the Digest correctly predicted that Harding would be elected.In elections that followed,

23、the magazine expanded the size of its poll,and made correct predictions in 1924,1928,and 1932.In 1936,based on two million respondents answers,the Digest predicted that Republican candidate Alf Landon would get 57%ballots and incumbent President Franklin Roosevelt would get only 43%.Two weeks later,

24、voters gave Roosevelt a third term in office by the largest landslide in history,with 61 per cent of the vote.The problem lay in the sampling frame used:telephone subscribers and automobile owners.Such a sampling design selected a disproportionately wealthy people,especially coming on the tail end o

25、f the worst economic depression in the nation history.l(continued)lIn contrast to the Literacy Digest,George Gallup correctly predicted that Roosevelt would beat Landon.Gallups success in 1936 hinged on his use of quota sampling.lQuota sampling is based on a knowledge of the characteristics of the p

26、opulation being sampled:what proportion are men,what proportion women,what proportions are of various incomes,ages,etc.People are selected to match the population characteristics.i.1.Element（研究单位）.An element is that unit about which information is collected and which provides the basis of analysis.T

27、ypically,in survey research,elements are people or certain types of people.However,other kinds of units can constitute the elements for social research;families,social clubs,or corporations might be the elements of a study.(Note:Elements and units of analysis are often the same in a given study,thou

28、gh the former refers to sample selection while the latter refers to data analysis.)l1.Population(总体).A population is the theoretically specified aggregation of study elements.For example,specifying the term“college students”would include a consideration of full-time and part-time students,degree can

29、didates and non-degree candidates,undergraduate and graduate students,and similar issues.l2.Study Population（研究总体）.A study population is that aggregation of elements from which the sample is actually selected.As a practical matter,you are seldom in a position to guarantee that every element meeting

30、the theoretical definitions laid down actually has a chance of being selected in the sample.Even where lists of elements exist for sampling purposes,the lists are usually somewhat incomplete.Some students are always omitted,inadvertently,from student roster.Some telephone subscribers request that th

31、eir names and numbers be unlisted.The study population,then,is the aggregation of elements from which the sample is selected.l3.Sampling Unit（抽样单位）.A sampling unit is that element or set of elements considered for selection in some stage of sampling.In a simple,single-stage sample,the sampling units

32、 are the same as the elements.In more complex samples,however,different levels of sampling units may be employed.For example,you might select a sample of census blocks in a city,then select a sample of households on the selected blocks,and finally select a sample of adults from selected households.l

33、4.Sampling Frame（抽样框）.A sampling frame is the actual list of sampling units from which the sample,or some stage of the sample,is selected.l5.Observation Unit（观察单位）.An observation unit,or unit of data collection,is an elements from which information is collected.Again,the unit of analysis and unit of

34、 observation are often the samethe individual personbut that need not be the case.Thus the researcher may interview heads of households(the observation unit)to collect information about all family members of the households(the units of analysis).l6.Variable（变量）.A variable is a set of mutually exclus

35、ive attributes:sex,age,employment status,and so forth.l7.Parameter（参数值）.A parameter is the summary description of a given variable in a population.l8.Statistic（统计值）.A statistic is the summary description of a given variable in a sample.Sample statistics are used to make estimates of population param

36、eters.l9.Sampling Error（抽样误差）.Probability sampling methods seldom,if ever,provide statistics exactly equal to the parameters that they are used to estimate.Probability theory,however,permits us to estimate the degree of error to be expected for a given sample design.l10.Confidence Levels and Confide

37、nce Intervals（显著性水平与置信区间）.We express the accuracy of our sample statistics in terms of a level of confidence that the statistics fall within a specified interval from the parameter.For example,we may say we are 95 percent confident that our sample statistics are within plus or minus 5 percentage poi

38、nts of the population parameter.lSimple Random Sampling(简单随机抽样).A type of probability sample in which the units composing a population are assigned numbers,a set of random numbers is then generated,and the units having those numbers are included in the sample.Although probability theory and the calc

39、ulations it provides assume this basic sampling method,it is seldom used for practical reasons.lSystematic Sampling(系统抽样).A type of probability sample in which every kth unit in a list is selected for inclusion in the sample:e.g.,every 25th student in the college directory of students.K is computed

40、by dividing the size of the population by the desired sample size and is called the sampling interval.Within certain constraints,systematic sampling is a functional equivalent of simple random sampling and usually easier to do.l Sampling interval=population size/sample sizel sampling ratio=sample si

41、ze/population sizeStratified sampling(分层抽样分层抽样):to organize the population into homogeneous subsets(with heterogeneity between subsets.)and to select the appropriate number of elements from each.lCluster Sampling(整群抽样).A multistage sample in which natural groups(clusters)are sampled initially,with t

42、he members of each selected group being subsampled afterward.For example,you might select a sample of U.S.colleges and universities from a directory,get lists of the students at all the selected schools,then draw samples of students from each.lPurposive or judgmental sampling(立意抽样).A type of nonprob

43、ability sampling in which you select the units to be observed on the basis of your own judgment about which ones will be the most useful or reprsentative.lQuota sampling(配额抽样).A type of non-probability sampling in which units are selected into the sample on the basis of prespecified characteristics,

44、so that the total sample will have the same distribution of characteristics as are assumed to exist in the population being studied.lSnowball sampling(滚雪球抽样).A non-probability sampling method often employed in filed research.Each person interviewed may be asked to suggest additional people for inter

45、viewing.lA.population size 样本规模lB.population heterogeneity 样本异质性l variance(方差)lC.permited sampling error 允许抽样误差l4.1 Operationalization and Social MeasurementlA.Operationalization of Research Project（研究课题的操作化）lB.Social Measurement（社会测量）4.2 Levels of Social Measurement A.Nominal Measure（定类测量）B.Ordinal

46、 Measure（定序测量）C.Interval Measure（定距测量）D.Ratio measure（定比测量）l4.3.Reliability and Validity lA.Reliability（信度）lB.Validity（效度）lC.Relations between reliability and validitylA.Operationalization of Research Projecta.Operational definition of conceptlOperational definitiona definition that spells out preci

47、sely how the concept will be measured.Strictly speaking,an operational definition is a description of the“operations”that will be undertaken in measuring a concept.b.Choice of indexeslExample:Economic development-annual income per capita;collective income Intelligence-Couple relation-c.Operationaliz

48、ation of hypothesislConcept:Industrialization-Human relationlIndex:industrial output-times visiting each otherl phone subscribers l Conceptualizationl l Nominal definitionl l Operational definitionlmeasurements in the real worldlDefinition:in order to understand the nature,characteristics and condit

49、ions of the objects,we allocate some numbers or symbols to the objects according to some regulations.This process is called social measurement.lThree elements of social measurement Objects Number or symbols regulationslA.Nominal MeasurelVariables whose attributes have only the characteristics of exh

50、austiveness and mutual exclusiveness are nominal variables.Examples of these would be sex,religious affiliation,political party affiliation,birthplace,college major,and hair color.lB.Ordinal MeasurelVariables whose attributes may be logically rank-ordered are ordinal measures.The different attribute