皮尤調查的方法論

【Comment】

翻譯請指正，裡面有專業內容。

美國的皮尤，在全國性調查中，市內電話與手機，是1：3。

依據的事實是：僅有市話卻無手機的，僅佔3％。

台灣該是多少。

「民意調查與實際選舉結果的比較，提供了驗證調查結果的機會」

台灣，沒有驗證過。無從知道，正當的權重要如何下。

Our survey methodology in detail    PEW / Taimcracy翻譯

Sampling取樣

The typical Pew Research Center national survey selects a random digit sample of both landline and cellphone numbers in all 50 U.S. states and the District of Columbia.  As the proportion of Americans who rely solely or mostly on cellphones for their telephone service continues to grow, sampling both landline and cellphone numbers helps to ensure that our surveys represent all adults who have access to either (only about 3% of households in the U.S. do not have access to any phone).  We sample landline and cellphone numbers to yield a combined sample with approximately 25% of the interviews conducted by landline and 75% by cellphone.  This ratio is based on an analysis that attempts to balance cost and fieldwork considerations as well as to improve the overall demographic composition of the sample (in terms of age, race/ethnicity and education).  This ratio also ensures an adequate number of cell-only respondents in each survey.

典型的皮尤研究中心全國調查選擇了美國所有50個州，和哥倫比亞特區的固定電話號碼和手機號碼的隨機數字樣本。由於完全依賴或主要依靠手機進行電話服務的美國人比例持續增長，因此，對固定電話號碼和手機號碼進行抽樣，有助於確保我們的調查，可以代表所有接電話的成年人（美國僅有約3％的家庭無法使用任何手機）。我們對固定電話和手機號碼進行抽樣，得出合併後的樣本，其中大約25％的訪談是通過固定電話進行的，75％是通過手機進行的。該比率基於一項分析，該分析試圖平衡成本和實地工作的考慮因素，並改善樣本的總體人口構成（在年齡，種族/民族和教育方面）。該比率還確保每次調查中有足夠數量的僅細胞受訪者。

The design of the landline sample ensures representation of both listed and unlisted numbers (including those not yet listed) by using random digit dialing.  This method uses random generation of the last two digits of telephone numbers selected on the basis of the area code, telephone exchange and bank number.   

A bank is defined as 100 contiguous telephone numbers, for example 800-555-1200 to 800-555-1299.  The telephone exchanges are selected to be proportionally stratified by county and by telephone exchange within the county.  That is, the number of telephone numbers randomly sampled from within a given county is proportional to that county’s share of telephone numbers in the U.S.  Only banks of telephone numbers containing one or more listed residential numbers are selected.

固定電話樣本的設計，是透過使用隨機數字撥號，確保列出和未列出的號碼（包括尚未列出的號碼）。該方法使用隨機生成基於區號，電話交換機和銀行號碼選擇的電話號碼的最後兩位數字。資料庫被定義為100個連續電話號碼，例如800-555-1200到800-555-1299。選擇的電話交換機，按縣和縣內的電話交換按比例分層。也就是說，從特定郡縣內隨機抽樣的電話號碼的數量，與該縣在美國的電話號碼的成比例。僅包含了一個或多個列出的住宅號碼的電話號碼的資料庫才會被挑選出來。

The cellphone sample is drawn through systematic sampling from dedicated wireless banks of 100 contiguous numbers and shared service banks with no directory-listed landline numbers (to ensure that the cellphone sample does not include banks that are also included in the landline sample).  The sample is designed to be representative both geographically and by large and small wireless carriers (also see cellphones for more information).

手機樣本抽取自100個連續號碼的專用無線資料庫，和沒有電話號碼簿的共享服務資料庫，出的固定電話號碼（以確保手機樣本不包括固定電話樣本）。該樣本被設計為具有地理位置和大型和小型無線運營商的代表（有關更多訊息，請參見手機）。

Both the landline and cell samples are released for interviewing in replicates, which are small random samples of each larger sample.  Using replicates to control the release of telephone numbers ensures that the complete call procedures are followed for all numbers dialed.  The use of replicates also improves the overall representativeness of the survey by helping to ensure that the regional distribution of numbers called is appropriate.

固定電話和手機樣本，都複製到供訪談用，使每個較大樣本群中的小隨機樣本。使用複製，以控制電話號碼能確保所有撥打的號碼，都遵循完整的電訪程序。複製的使用還透過幫助確保所調用的數字的區域分佈，是適當的來改善調查的總體代表性。

When interviewers reach someone on a landline phone, they randomly ask half the sample if they could speak with “the youngest male, 18 years of age or older, who is now at home” and the other half of the sample to speak with “the youngest female, 18 years of age or older, who is now at home.”  If there is no eligible person of the requested gender currently at home, interviewers ask to speak with the youngest adult of the opposite gender, who is now at home.  This method of selecting respondents within each household improves participation among young people who are often more difficult to interview than older people because of their lifestyles.

當面試官通過固定電話聯繫某人時，他們會隨機詢問一半的樣本，是否可以與「最年輕的男性，18歲或以上的人，現在在家裡的」進行交談，另一半的樣本與「最年輕的女性，18歲或以上，現在在家的。」如果目前在家中沒有符合要求的性別的合格人員，電訪員要求與現在在家的最年輕的異性成年人交談。這種在每個家庭中選擇受訪者的方法，可以提高年輕人的參與度，因為他們的生活方式，這些年輕人通常比老年人更難以面談。

Unlike a landline phone, a cellphone is assumed in Pew Research Center polls to be a personal device.  Interviewers ask if the person who answers the cellphone is 18 years of age or older to determine if the person is eligible to complete the survey (also see cellphone surveys for more information).  This means that, for those in the cell sample, no effort is made to give other household members a chance to be interviewed.  lthough some people share cellphones, it is still uncertain whether the benefits of sampling among the users of a shared cellphone outweigh the disadvantages.

與固定電話不同，皮尤研究中心民意調查顯示：手機是個人設備。採訪者詢問接聽手機的人是否年滿18歲或以上，以確定該人是否有資格完成調查（有關更多信息，請參閱手機調查）。這意味著，對於手機樣本中的那些人，沒有辦法讓其他家庭成員，有機會接受訪談。雖然有些人共用手機，但仍然不確定共享手機用戶的抽樣優點是否超過缺點。

Sampling error results from collecting data from some, rather than all, members of the population. For each of our surveys, we report a margin of sampling error for the total sample and usually for key subgroups analyzed in the report (e.g., registered voters, Democrats, Republicans, etc.).  For example, the sampling error for a typical Pew Research Center national survey of 1,500 completed interviews is plus or minus 2.9 percentage points with a 95% confidence interval.  This means that in 95 out of every 100 samples of the same size and type, the results we obtain would vary by no more than plus or minus 2.9 percentage points from the result we would get if we could interview every member of the population.  Thus, the chances are very high (95 out of 100) that any sample we draw will be within 3 points of the true population value.  The sampling errors we report also take into account the effect of weighting. (Also see probability and non-probability sampling for more information.)

採樣錯誤來自收集來自一些人群而非全部成員的數據。對於我們的每個調查，我們報告總樣本的抽樣誤差幅度，通常是報告中分析的關鍵子群（例如，登記選民，民主黨人，共和黨人等）。例如，典型的皮尤研究中心全國1,500次訪談調查的抽樣誤差為正負2.9個百分點，信賴區間為95％。這意味著，在每100個相同大小和類型的樣本中，95個中我們獲得的結果，與我們可以訪問每個成員的結果相差不超過±2.9個百分點。因此，我們繪製的任何樣本，都在真實人口價值的3個百分點內的可能性非常高（100個中的95個）。我們報告的抽樣誤差，也考慮了加權的影響。（有關更多信息，請參閱概率和非概率抽樣。）

Nonresponse無回應

At least seven attempts are made to complete an interview at every sampled telephone number. The calls are staggered over times of day and days of the week (including at least one daytime call) to maximize the chances of making contact with a potential respondent. Interviewing is also spread as evenly as possible across the field period. An effort is made to recontact most interview breakoffs and refusals to attempt to convert them to completed interviews.

在每個抽樣的電話號碼上，至少要進行七次嘗試，以完成一次採訪。這些電話在一天中的幾天，和一周中的幾天（包括至少一個白天電話）交錯，以最大限度地提高與潛在受訪者聯繫的機會。採訪也在整個實地期間，盡可能均勻地傳播。我們努力重新調整大多數面試中斷和拒絕，以試圖將他們轉換為完成的面試。

Response rates for Pew Research polls typically range from 5% to 15%; these response rates are comparable to those for other major opinion polls.  The response rate is the percentage of known or assumed residential households for which a completed interview was obtained.  The response rate we report is computed using the American Association for Public Opinion Research’s (AAPOR) Response Rate 3 (RR3) method.  (For a full discussion of response rates, see AAPOR’s Standard Definitions.)  Fortunately, low response rates are not necessarily an indication of nonresponse bias, as we discuss in the problem of declining response rates.

皮尤民意調查的回覆率通常在5％至15％之間；這些回覆率與其他主要民意調查的回覆率相當。回覆率是獲得完成訪談的已知或假設住宅家庭的百分比。我們報告的回覆率是使用美國公共輿論研究協會（AAPOR）回應率3（RR3）方法計算的。（有關回覆率的完整討論，請參閱AAPOR的標准定義。）所幸，低回覆率並不一定表示無回應偏差，正如我們在回覆率下降的問題中所討論的那樣。

In addition to the response rate, we sometimes report the contact rate, cooperation rate or the completion rate for a survey. The contact rate is the proportion of working numbers where a request for an interview was made. The cooperation rate is the proportion of contacted numbers where someone gave initial consent to be interviewed. The completion rate is the proportion of initially cooperating and eligible households where someone completed the interview.

除了回覆率，我們有時會報告調查的聯繫率，合作率或完成率。聯繫率是進行面試請求的工作人數的比例。合作率是有人初步同意接受訪談的聯繫號碼的比例。完成率是有人完成訪談的初始合作和符合條件的家庭的比例。

Data weighting數據加權

Nonresponse in telephone interview surveys can produce biases in survey-derived estimates.  Survey participation tends to vary for different subgroups of the population, and these subgroups are likely to also vary on questions of substantive interest.  To compensate for these known biases, the sample data are weighted for analysis.

電話訪問調查中的無回應，可能會產生調查的估計偏差。調查參與往往因人口次族群的不同而異，並且這些子群在具體利益問題上，也可能不同。為了補償這些已知的偏差，對樣本數據進行加權以進行分析。

The landline sample is first weighted by household size to account for the fact that people in larger households have a lower probability of being selected.  In addition, the combined landline and cellphone sample is weighted to account for the fact that respondents with both a landline and cellphone have a greater probability of being included in the sample.

首先按家庭規模加權固定電話樣本，以說明較大家庭中的人選擇概率較低的事實。此外，整合固定電話和手機樣本的加權，是為了讓固定電話和手機的受訪者盡可能被納入樣本。

The sample is then weighted using population parameters from the U.S. Census Bureau for adults 18 years of age or older.  The population parameters used for weighting are: gender by age; gender by education; age by education; region; race and Hispanic origin, which includes a break for Hispanics based on whether they were born in the U.S. or not; population density; and among non-Hispanic whites – age, education and region.  The parameters for these variables are from the Census Bureau’s American Community Survey (excluding those in institutionalized group quarters), except for the parameter for population density, which is from the 2010 census.  These population parameters are compared with the sample characteristics to construct the weights.  In addition to the demographic parameters, the sample is also weighted to match current patterns of telephone status (landline only, cellphone only or both landline and cellphone), based on extrapolations from the National Health Interview Survey.  The final weights are derived using an iterative technique that simultaneously balances the distributions of all weighting parameters.  These are the standard demographics we ask on our telephone polls in order to weight and analyze the data.  You can also access the version of these demographics that we use on Web surveys, as well as the Spanish phone and Spanish Web versions.

然後使用來自美國人口普查局的人口參數，對18歲或以上的成年人進行加權。用於加權的人口參數是：按年齡劃分的性別；受教育的性別；受教育年齡；區域；種族和西班牙裔，包括西班牙裔美國人是否出生在美國；人口密度；和非西班牙裔白人 - 年齡，教育和地區。這些變量的參數，來自人口普查局的美國社區調查（不包括群體宿舍中的那些），人口密度參數除外，該參數來自2010年人口普查。將這些群體參數與樣本特徵進行比較以構建權重。除了人口統計參數之外，還根據國家健康訪談調查的推估，對樣本進行加權，以匹配當前的電話狀態模式（僅限固定電話，僅限手機，或固定電話加手機）。最終權重比，是來自互動技術導出，該技術能同時平衡所有加權參數的分佈。這些是我們在電話民意調查中要求的標准人口統計數據，以便對數據進行加權和分析。您還可以上我們在網絡調查中使用的這些受眾特徵的版本，以及西班牙語電話和西班牙語網路版本。

Weighting cannot eliminate every source of nonresponse bias.  Nonetheless, properly conducted public opinion polls have a good record in achieving unbiased samples.  In particular, election polling –  where a comparison of the polls with the actual election results provides an opportunity to validate the survey results – has been very accurate over the years (see the National Council on Public Polls’ evaluations of the 2012 and 2010 elections).

加權不能消除每個無回應的來源偏差。儘管如此，正確進行的民意調查在取得無偏見樣本方面，仍有良好記錄。特別是，選舉民意調查 - 民意調查與實際選舉結果的比較，提供了驗證調查結果的機會 - 多年來一直非常準確（參見全國民意調查委員會對2012年和2010年選舉的評估） 。

Data analysis數據分析

Each Pew Research survey report includes a “topline questionnaire” with all of the questions from that survey with the exact question wording and response options as they were read to respondents.  This topline provides the results from the current survey for each question, as well as results from previous surveys in which the same or similar questions were asked.

每份PEW的調查報告都包含一份「頭條問卷」，其中包含該調查中的所有問題，以及給受訪者閱讀的提問的精確措辭，和回答選項。該頭條問卷，提供了每個問題的當前調查結果，以及之前詢問了相同或類似問題的調查的結果。

For discussion of the results in reports and commentaries, differences among groups are reported when we have determined that the relationship is statistically significant and therefore is unlikely to occur by chance.  Statistical tests of significance take into account the effect of weighting.  In addition, to support any causal relationships discussed, more advanced multivariate statistical modeling techniques are often employed to test whether these connections exist, although the results of these models may or may not be shown in the actual report.

為了討論報告和評論中的結果，當我們確定這種關係具有統計學意義，並因此不太可能偶然發生時，報告的群體之間存在差異。重要性的統計檢驗，則考慮了加權的影響。此外，為了支持所討論的任何因果關係，通常採用更先進的多變量統計建模技術來測試這些連接是否存在，儘管這些模型的結果可能會或可能不會在實際報告中顯示。

For most studies, it is our policy to release datasets from Pew Research surveys five months after the data were collected and archive them on our website as quickly as possible.  Please visit our datasets page for further information.

對於大多數研究，我們的政策是在收集數據五個月後從尤調查中發布數據，並儘快將其上傳在我們的網站上。請上我們的數據集頁面，獲取更多訊息。