流行病学数据的搜集.ppt

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1、流行病学数据的搜集Collection of Epidemiologic Data,朱保平，医学博士，生物统计学硕士Bao-Ping Zhu,MD,MS中国现场流行病学培训项目常驻指导专家U.S.Resident Expert Advisor to China FETP,现场流行病学数据的类别Types of epidemiologic data,结果数据 Outcome data暴露数据 Exposure data其他相关危险因素的数据 Data on related risk factors,流行病学数据的来源Sources of epidemiologic data,现成数据 Exist

2、ing data需搜集的数据 Data to be collected,常见现成数据Examples of existing data,人口统计学数据 Population data人口普查数据 Census data普查年间的估计数 Inter-census estimates生命统计数据 Vital statistics data出生登记 Birth registry死亡登记 Death data结婚、离婚数据 Marriage and divorce监测数据 Surveillance data疾病监测 Disease surveillance健康危险因素监测 Behavioral ris

3、k factors surveillance,常见现成数据Examples of existing data,健康状况和行为数据 Health status and behavioral data健康和营养调查 Health and nutrition surveillance行为危险因素调查 Behavioral risk factor surveillance社会经济学数据 Socioeconomic data消费者价格指数,国民生产总值,失业率 CPI,GNP,unemployment rate行政管理数据 Administrative data门诊记录 Outpatient recor

4、ds住院记录 Hospitalization data实验室检查记录 Laboratory testing data,流行病学数据的搜集方法 Methods for collecting epidemiologic data,自填式调查表 Self-administered questionnaire面对面调查 Personal interviews对生物标本进行生化检测 Biochemical analysis of biological specimens对环境进行物理、化学分析 Physical or chemical analysis of the environment,流行病学数据

5、的等级Scales of Epidemiologic Data,定性数据 Nominal性别，职业 Gender;occupation;race/ethnicity定序数据 Ordinal社会经济状况 Socioeconomic status:low,medium,high区间数据 Interval温度 Temperature出生年份 Year of birth比率数据 Ratio data体重 Weight身高 Height,优先考虑收集高等级数据Higher scale data are always preferred,提供更丰富的信息 Richer information统计学效力更高

6、 Higher statistical power统计分析方法有更多的选择 More options for statistical analysis可转换成低等级数据 Higher scale data may be transformed into lower scale data而低等级数据无法变成高等级数据 Lower scale data may not be transformed into higher scale data,数据的质量取决于所使用的测量工具 Data is only as good as the measurement instrument used,每次对某特

7、征进行测量，我们都希望得到“真实”情况 We would like to measure the“truth”every time we measure a characteristic如果达不到这个目标，就意味着有测量误差 Any deviation from this constitutes a measurement error描述测量误差的两个指标可靠性 Reliability可信性 Validity,可靠性 Reliability,对研究对象进行多次测量，所得到信息的是否相似 Refers to the degree of similarity of information obta

8、ined when the measurement is repeated in the same subject每次测量的结果是否都相同？Is the same value arrived at every time the measurement is taken/made?,可信性 Validity,测量结果是否反映真实情况？Is it a true reflection of what you want to measure?在进行重复测量时，若测量值与真实值相比系统地偏高或偏低，则我们就说可信性较低 A measure lacks validity if an observer or

9、 an instrument measures the characteristic in the same individual repeatedly higher or repeatedly lower than the real value这种系统性误差即“偏差”或“偏倚”This systematic error introduces a bias一个可靠性好的测量值，其可信性可能仍然较低 A measure can be reliable but not valid,可信性与可靠性之间的关系Validity and Reliability,可靠但不可信,可信但不可靠,既不可靠亦不可信

10、,既可靠亦可信,箭靶的比喻 The Target metaphor,测量误差的来源 The sources of error in measurement,测量工具 The instrument在对同一个研究对象进行测量时，测量工具本身可能有前后差异 The instrument itself gives different results for the same individual例如，血压袖带放置位置不同 e.g.blood pressure cuff测量人员 The observer不同测量人员之间的差别 Inter-observer variation-differences am

11、ong observers同一测量人员不同次之间的差别 Intra-observer variation-differences in the same observer,测量误差的来源 The sources of error in measurement,被测量者 The subject生物学上的不一致性 Biological inconsistencies记忆偏差 Memory测量时的环境 The environment温度 Temperature湿度 Humidity,问卷 Questionnaires,设计一个好的问卷需要花时间和精力 A good questionnaire tak

12、es time and effort to design不要低估这一点的重要性！Dont underestimate this!问卷中所包含的问题的你确实需要的问题！The questionnaire should only collect that information that you need for the study例：人口学，暴露，结局的信息 e.g.Demographics/Exposure/Outcome设计问卷前先考虑你所研究的问题和分析计划 Think about the research questions and analysis plan例：是只想知道有无暴露，还是

13、也想知道暴露剂量？e.g.Are you only interested in exposure(Y/N)or are you also interested in dose?,调查表设计的十个步骤Steps in questionnaire design,确立调查内容或待验假设 State the research question(s)/hypotheses拟定分析计划 Outline an analysis plan(“empty”tables)列出需要要测量的变量 List the variables to be measured确定调查如何进行 Decide how the ques

14、tionnaire will be administered拟定要问的问题 Formulate the questions问哪些问题？Decide on the questions如何表述？Phrase the questions确定问题的顺序 Determine the sequence of questions设计调查表的布局 Plan the layout and design of the questionnaire必要时把调查表翻译成当地语言 Translate if necessary培训调查员 Train interviewers预调查 Pilot test,确立调查内容或待验假

15、设 State the Research Questions or Hypotheses,提出假设以指导资料的搜集 Generate hypotheses to guide data collection描述流行病学 Review descriptive studies 分析“异常值”为何异常 Look and learn from outliers与他人讨论 Talk to people与当地业务人员座谈讨论 Talk to local officials去现场考察环境 Go to field and study the environment,调查开始前思考要验证的假设。比如：Think

16、about questions and related outcomes in advance.For examples:接触病例与发病相关 Contact with a case is associated with illness疫苗对疾病有保护作用 Vaccine is associated with protection from illness喝牛奶与疾病有关联 Milk is associated with illness疾病与喝牛奶的量有关联 Illness was associated with the amount of milk consumed在这些情况下，需要对哪些暴露

17、因素和结果进行测量？What exposures and outcomes do we specifically want to measure?,确立调查内容或待验假设State the Research Questions or Hypotheses,调查表设计的十个步骤Steps in questionnaire design,确立调查内容或待验假设 State the research question(s)/hypotheses拟定分析计划 Outline an analysis plan(“empty”tables)列出需要要测量的变量 List the variables to

18、be measured确定调查如何进行 Decide how the questionnaire will be administered拟定要问的问题 Formulate the questions问哪些问题？Decide on the questions如何表述？Phrase the questions确定问题的顺序 Determine the sequence of questions设计调查表的布局 Plan the layout and design of the questionnaire必要时把调查表翻译成当地语言 Translate if necessary培训调查员 Trai

19、n interviewers预调查 Pilot test,制订分析大纲（空白表）Outline an analysis plan(empty tables),用哪一种关联的指标？What measure of association will be used?哪些关联是我所感兴趣的？Which associations am I interested in?,接触过病例 Contact with case,未接触病例 No Contact with case,发病Ill,未发病Not Ill,需要对接触进行测量 We need a measure of contact!,需要对疾病进行定义或测

20、量 We need to measure/define illness!,调查表设计的十个步骤Steps in questionnaire design,确立调查内容或待验假设 State the research question(s)/hypotheses拟定分析计划 Outline an analysis plan(“empty”tables)列出需要要测量的变量 List the variables to be measured确定调查如何进行 Decide how the questionnaire will be administered拟定要问的问题 Formulate the

21、questions问哪些问题？Decide on the questions如何表述？Phrase the questions确定问题的顺序 Determine the sequence of questions设计调查表的布局 Plan the layout and design of the questionnaire必要时把调查表翻译成当地语言 Translate if necessary培训调查员 Train interviewers预调查 Pilot test,列出需要收集的变量Variables to be collected(observed or measured),被调查者

22、The participant基本资料，如姓名，号码Participant(Name,ID#)地址，年龄，性别，职业Address,age,sex,occupation,etc.暴露 The exposure有无，地点，时间，剂量，持续时间If/where/when/how much/how long结局 The outcome症状，体征，检验结果 Symptoms/signs/tests,可以用调查表来采集的信息Information that may be collected with a questionnaire,个人特征 Individual characteristics 身高，年

23、龄，收入 Height,age,income环境 Environment 住房情况，家庭成员数 Housing,family size行为，习惯 Behaviors,practices饮酒，吸烟 Alcohol or tobacco consumption判断 Judgements意见 Opinions态度 Attitudes衡量知识的指标 Indicators of knowledge有关危险因素的知识 Risk factors对健康生活习惯的认识 Healthy lifestyle,调查表设计的十个步骤Steps in questionnaire design,确立调查内容或待验假设 St

24、ate the research question(s)/hypotheses拟定分析计划 Outline an analysis plan(“empty”tables)列出需要要测量的变量 List the variables to be measured确定调查如何进行 Decide how the questionnaire will be administered拟定要问的问题 Formulate the questions问哪些问题？Decide on the questions如何表述？Phrase the questions确定问题的顺序 Determine the sequen

25、ce of questions设计调查表的布局 Plan the layout and design of the questionnaire必要时把调查表翻译成当地语言 Translate if necessary培训调查员 Train interviewers预调查 Pilot test,获得信息的常用方法Methods of obtaining information,自填式调查表 Self-administered questionnaire 邮寄调查表 Mail(postal)网上调查 Web-based调查员监督下自填 Monitored调查员填写的调查表 Interviewer-

26、administered questionnaire电话调查 By telephone面对面问卷 In person,选择什么样的方法？What method to choose?,问题的性质 Nature of questions问的是什么样的问题？What is the research question to be addressed?方便 Convenience哪一方法最方便？Which method is most readily available?花费 Cost需要How costly is it to collect the information and how afford

27、able is the method?,如何开展问卷调查 Questionnaire administration,面对面调查 In-person interviewing最常用的一种方法 Most frequently used优点：应答率较高；有弹性 High response rates;flexibility缺点：费时；能造成观察者偏倚 Time consuming;potential observer bias电话调查 Telephone interviews优点：花费少；快；可在大范围内实施 Inexpensive;rapid;large numbers or area缺点：无应答

28、较高；没有面对面交流；调查时间仓促；可能造成观察者偏倚 Non-response;no visual cues;rushed;potential observer bias邮寄调查表 Postal Questionnaires优点：花费少；快速；可以在大范围内进行 Inexpensive;rapid;large numbers or area缺点：无应答较高；组织起来复杂 Non-response;complexity,调查表设计的十个步骤Steps in questionnaire design,确立调查内容或待验假设 State the research question(s)/hypot

29、heses拟定分析计划 Outline an analysis plan(“empty”tables)列出需要要测量的变量 List the variables to be measured确定调查如何进行 Decide how the questionnaire will be administered拟定要问的问题 Formulate the questions问哪些问题？Decide on the questions如何表述？Phrase the questions确定问题的顺序 Determine the sequence of questions设计调查表的布局 Plan the l

30、ayout and design of the questionnaire必要时把调查表翻译成当地语言 Translate if necessary培训调查员 Train interviewers预调查 Pilot test,问题的类别 Types of Questions,事实性的问题 Factual人口学，实验室，临床信息 Demographic,laboratory,clinical information观点与态度 Opinions and Attitudes与研究有关的信念，想法，前设，价值观，等等 Beliefs,ideas,predispositions,and values r

31、elated to the topic under study信息，知识 Information/knowledge检验的是被调查者知道什么（有没有某种知识）Measures what people know(presence or absence of knowledge)正确与错误的知识 Correct or incorrect knowledge,行为 Behavior对行为进行描述 Description of behavior人们报告的行为与实际行为是否符合很难判断 Difficult to evaluate how people think they behave vs.what

32、they actually do量表 对被调查者问一系列问题，合起来对某一变量进行描述 Constructs responses to multiple questions are combined to estimate a particular variable 社会经济状况量表 Socio-economic status(SES)生活质量量表 Quality of life改变某一行为效力的量表 Self efficacy to change a behavior,问题的类别 Types of Questions,剂量-效应关系Measuring Dose-Response Relati

33、onship,洗手频度与诺如病毒感染发病的关系饭前洗手习惯：每次 经常 偶尔 从不上厕所后洗手习惯：每次 经常 偶尔 从不玩耍后洗手习惯：每次 经常 偶尔 从不洗手时用肥皂情况：每次 经常 偶尔 从不平均每天洗手几次？_次喝豆汁与霍乱发病的关系（调查员用统一的杯子）像这样大小的杯子，你喝了几杯豆汁？_杯麻疹传播在网吧中的传播从开学到发烧前的一段时间里，你平均每天在网吧上网时间：“乾坤”网吧：每天_小时“天天”网吧：每天_小时“网虫”网吧：每天_小时,病例对照研究中的调查表Measuring Dose-Response Relationship,用尽量相同的调查表问的方法要一致，如：病例用电话调

34、查，对照也用电话调查问的次数要一致,协助工具Aids to recall,统一的容器这样大小的水杯，喝几杯水？照片不常吃的食物饮用水的品牌帮助回忆日期日历必要时使用农历使用重要事件或日期（如春节，结婚）帮助记忆,某村庄甲肝爆发A hepatitis A outbreak,待验假设：11月后的高峰是由于饮用某个品牌桶的装水导致点源爆发,如何询问病例和对照的暴露史？需要考虑的问题：甲肝的潜伏期很长很难回忆3天以上的饮食史病例对饮食的回忆比对照要好,询问习惯性的问题Ask Preference Questions,你平常的饮水类型是：桶装(饮水机)水：经常 有时 偶尔 很少 从不自来水：经常 有时

35、偶尔 很少 从不自家井水：经常 有时 偶尔 很少 从不饮水习惯：如喝桶装水，习惯于喝：热水 温水 凉水 兑着喝如喝自来水或井水，习惯于喝：开水（热或凉）生水 生水、开水兑着喝,调查表设计中的常见问题Common Problems,模棱两可 Ambiguous questions问题不清楚 Not self-explanatory一道题中问两个问题 Two questions in one(compound questions)语言复杂 Complex words所问的问题无法回忆 Asking things that people wont remember假定的问题 Hypothetical

36、 questions可供选择的类别不够 Not enough categories太长，或有太多的概念 Too long or too many ideas类别之间有重复 Overlapping categories开场白有问题 Leading questions问题的准确度无法界定 Degree of accuracy not specified,解决办法Questionnaire Solutions,使用简单的语言 Simple language 将问题分成几步来问 Staged questions将答案分成等级 Scaling提供图像帮助 Visual clues预调查 Pilot te

37、sts,注意界定资料格式Be clear about the data format you want!,日期Date:12/10/0610/12/0606/10/12,年龄 Age:9（是9岁还是9个月？）(What?Years or months),?,?,格式不确定 Unspecified Format,问题的格式Format of questions,封闭式：答案已预先确定 Closed format give a fixed response简单、易填 Simple and quick;easy to use in the field减少了文化程度低的人回答的障碍 Reduces d

38、iscrimination against those who are less literate 容易进行编码、录入、定量分析 Easy to code,record,and analyze results quantitatively 容易报告结果 Easy to report results 限制了收集数据的种类和量 Limits the variety and amount of data collected,开放式:允许自由发挥 Open-ended format allows exploration of issues当需要让被调查者先提供信息，然后再问特定问题时 When the

39、re is interest in what information a subject will volunteer before asking a specific response当进行定量研究，或需要文字描述性数据时When conducting qualitative research;when verbatim responses are needed in a report当可能答案太多而无法界定时仍可使用 Can be used even if a comprehensive range of alternative choices cannot be compiled不容易实

40、施和记录 Not easy to administer and record资料编码、分析和定量分析时比较困难 Difficult to code responses,analyze data,and quantify results,问题的格式Format of questions,开放式问题 Open Question,你吃/喝过那些奶制品？What milk products have you eaten?_,封闭式问题：是/否Closed question:Yes/No,你有以下症状吗？Did you have any of the following symptoms?是Yes 否N

41、o不清楚 Unsure腹泻 Diarrhea发热 Fever腹痛 Abdominal pain呕吐 Vomiting其他 Other,分阶段的问题Staged Questions,在那个聚会中你是否喝苹果汁，喝了多少？Did you drink the apple juice at the party and how much did you drink?_或 OR你有没有喝苹果汁？Did you drink any apple juice?有Y 没有N如有，喝了多少？If“yes”then how much did you drink?1杯1 cup2杯2 cups3杯3 cups4杯或以上

42、4 cups+,命名性答案 Nominal response:病人的性别 What is the patients gender?1=男male 2=女 female定序性答案 Ordinal response(useful in ranking):请把你对下列食品的爱吃程度进行排序，1=最爱，5=最不爱 Please rank the following food items in degrees of how much you would like to eat with 1 being the highest and 5 being the lowest?_ 鸡肉 Chicken _ 牛

43、肉 Beef_ 马肉 Horse _ 鱼肉 Fish_ 羊肉 Sheep,其他形式的结构性问题Other Types of Structured Questions,用等级来衡量 Using Scales,请描述你疼痛的程度 How would you characterize the pain that you had?轻微Mild 中度 Moderate 重度Severe 或 OR请将你的疼痛程度按0-10分级 How would you characterize the pain that you had on a scale of 0 to 10?,10,0,1,2,3,4,5,6,7

44、,8,9,常见问题与陷阱 Problems and Pitfalls,避免“一题二问”；否则你无法知道回答者回答的是那件事 Avoid questions that ask two things at once-you wont know which bit people are answering:例如：你有脖子痛和腹泻的症状吗？有/没有e.g.Have you ever had neck pain and diarrhea?Yes/No?模棱两可 Ambiguity.例如：你上厕所次数很多吗？e.g.Do you go to the toilet a lot?,避免使用“行话”Avoid

45、jargon你参加过艾防知行活动吗？“艾防知行”=艾滋病防治知识与行为干预你打过流感裂解疫苗吗？许多人不知道什么是流感减毒苗，即使知道，可能也无法知道所打的是哪种疫苗避免各组间的重叠 Avoid options that are not mutually exclusive when they need to be你的年龄段 What age are you?16-2020-2525-3035-40,常见问题与陷阱 Problems and Pitfalls,避免暗示性问题 Avoid leading questions你认为是旅馆里的食物让你得病的吗？Do you think that th

46、e food in the hotel made you sick?你是不是觉得旅馆里的服务员看起来很不卫生？Did the hotel staff seem unhygienic to you?你觉得医院里的工作人员看起来是不是很累？Do you agree that the hospital staff were close to exhaustion?避免问卷过长 Avoid making the questionnaire too long避免错别字 Typographical/spelling errors学校的卫身环境如何有没有提供洗手夜发病前用了那些抗升素有没有打过易苗,常见问题

47、与陷阱 Problems and Pitfalls,调查表设计的十个步骤Steps in questionnaire design,确立调查内容或待验假设 State the research question(s)/hypotheses拟定分析计划 Outline an analysis plan(“empty”tables)列出需要要测量的变量 List the variables to be measured确定调查如何进行 Decide how the questionnaire will be administered拟定要问的问题 Formulate the questions问哪

48、些问题？Decide on the questions如何表述？Phrase the questions确定问题的顺序 Determine the sequence of questions设计调查表的布局 Plan the layout and design of the questionnaire必要时把调查表翻译成当地语言 Translate if necessary培训调查员 Train interviewers预调查 Pilot test,问题的顺序Sequence of Questions,将问题按照题目或回答方式来分组 Group questions by topic or re

49、sponse options问题的顺序很重要 Question order is important:由一般到特别 General to particular由易到难 Easy to difficult由具体到抽象 Factual to abstract从封闭式的问题开始问 Start with closed format questions从与本次调查有关、但敏感度小的问题开始问 Start with non-threatening questions relevant to the main subject不要把最重要的问题放在最后问 Dont put the most important

50、 item last,调查表设计的十个步骤Steps in questionnaire design,确立调查内容或待验假设 State the research question(s)/hypotheses拟定分析计划 Outline an analysis plan(“empty”tables)列出需要要测量的变量 List the variables to be measured确定调查如何进行 Decide how the questionnaire will be administered拟定要问的问题 Formulate the questions问哪些问题？Decide on t