How to use this repository.
This guide keeps a running list of the vendors, notes about them, and other practices for running repeated online panel experiments. The Design of Field Experiments With Survey Outcomes: A Framework for Selecting More Efficient, Robust, and Ethical Designs describes the design and an application study. This repository assumes knowledge of that paper.
Our companion paper Increasing Response Rates and Representativeness of Online Panels Recruited by Mail: Evidence from Experiments in 12 Original Surveys also contains recommendations on optimal incentives and anticipated response rates.
The power calculator available here allows one to plan out a study using the repeated online panel design and appreciate the benefits of this experimental design. The code for that power calcualtor is available in this repository here.
Have a question about using the design?
Please use the GitHub issues feature to ask a question or make a request. Then you'll get a ping when we answer the question or update the repository to answer it.
Civiqs offers all-in-one experiment administration services for the repeated survey design, using their custom-built online polling platform. They provide time-saving expert support and guidance for your project from start to finish, including mail, online surveys, data management, and incentive fulfillment. For more information, you can email email@example.com or visit www.civiqs.com/research. (Disclosure: the authors of this repository David Broockman and Joshua Kalla are volunteer members of Civiqs' scientific advisory board.)
Change-Point Analytics also offers a related service.
Vendors for Particular Pieces
For academic work, we prefer Qualtrics. Most universities have a subscription.
SurveyGizmo is a far cheaper alternative that may be preferable for practitioners. It is more difficult to program in our experience but workable.
Tango Card - Incentives
Tango Card is a service that sends gift cards to respondents via email. A POST request is issued to the Tango API and the respodent gets the gift card. There are no fees. However, one's Tango account must be loaded with funds in advance. We recommend university researchers begin this process far in advance, as onboarding Tango with one's university and then getting the university to transfer funds can both take weeks.
The Tango API accepts a POST request, but Qualtrics and SurveyGizmo are only capable of placing GET requests. A simple go-between is available here. We set up a server on Heroku that runs this go-between microservice.
Qualtrics does have a service called Blast Rewards that sends out gift cards to respondents using Tango. We are not familiar with how this works, but it may be easier than using the go-between.
See our companion paper Increasing Response Rates and Representativeness of Online Panels Recruited by Mail: Evidence from Experiments in 12 Original Surveys for recommendations on incentive amounts.
Brite Verify - Email Verification
We ask respondents for their email addresses and ask them to complete follow up surveys with solicitations sent to these email addresses. In our experience respondents often mistype their email addresses in the survey. We need them to correct these typos so that we can get their correct email. To detect these typos, we use the BriteVerify API, which assesses whether an email address is valid. It can be integrated directly into Qualtrics. An example is available here.
Twilio - Text Messages
We have sometimes given respondents the option of being texted when a follow-up survey is available. If they give their cell number and asked to be texted, we use a script available here to send text message with Twilio.
Google and Bing - Online Ads
Many respondents Google the name of the survey or Google the URL but do not enter the URL into their browser bars. Buying ads on Google and Bing allows one to redirect respondents to the survey. In our experience over 10% of respondents enter the survey via this mechanism. An example of the Google ad setup is available [here](baseline recruitment/search ads). Bing allows you to import Google ads, so we create the ads in Google first and then import them.
Voter file data
We use Snap Pack Mail.
See our example data cleaning code [here](data management/1_create_base_universe_mail_and_logins.do).
An example recruitment letter is available [here](baseline recruitment/Recruitment Letter Sample.png). Note that recruitment letters are often addressed to multiple people in a household, each of whom gets a unique login code.
There are also [specs](baseline recruitment/specs.txt) to give mail firms for cheaper rates. We recommend using standard mail with a pre-cancelled stamp affixed, and non-profit mail if applicable. If the experiment is taking place in a concentrated area, use PMOD shipping. Note that standard and non-profit mail can take 2 weeks to arrive. We recommend leaving multiple weeks for mail to arrive. PMOD shipping can speed this up somewhat. First class mail is significantly more expensive but also much faster.
In addition, [this image](baseline recruitment/how long to keep survey open.png) provides an example of how survey response rates grow over time once mail arrives. Many people respond right away but over 40% of responses come in over a week after mail arrives. This suggests one should leave the survey open for at least two weeks after mail arrives.
The recruitment letters contain unique login codes for each individual and a website that redirects them to the survey.
See our companion paper Increasing Response Rates and Representativeness of Online Panels Recruited by Mail: Evidence from Experiments in 12 Original Surveys for recommendations on recruitment letter text, survey naming, etc.
Website / Landing Page
The recruitment letter can direct respondents directly to the survey or to a landing page. Here's an example of a live landing page.
Survey questions usually fall into one of four buckets.
- Outcome measures
- Items might predict opinion change useful for modeling
- Filler questions unrelated to the broad outcome of interest (e.g., non-political questions)
- Ancillary non-experimental outcomes of independent interest
Example survey instruments are available here for a previous experiment using this design (see "Miami t0.pdf", etc.).
High reinterview rates are critical for the experimental design. With the below practices both university and non-university researchers have seen response rates over 75%. We have not tested the importance of these practices individually, however.
We ask respondents for their email addresses and ask them to complete follow up surveys with solicitations sent to these email addresses. Examples of these solicitaitons are available [here](reinterview recruitment/followup survey email reminders.png).
We usually send 3 or more emails per re-interview survey -- an original solicitation and at least two reminders. We leave the re-interview survey open for at least two weeks. [This](reinterview recruitment/how long to keep reinterview open.png) graph shows when responses come in.
As described above in the "Twilio" section we also send a text message to coincide with the first reinterview invitation email.
Rapid Incentive Delivery
We ensure the incentives for the baseline survey are sent promptly, and definitely before an invitation for a reinterview wave arrives.
As described above, a final factor helping reinterview rates is our use of BriteVerify -- this increases the share of emails at which we solicit reinterviews that are valid.
Treatment and Placebo Procedure
Our experimental design relies heavily on the use of placebo canvasses as a baseline comparison to a treatment canvass (Nickerson 2005). When using the placebo procedure, it is necessary that the types of voters canvassed with the treatment script are similar to those canvassed with the placebo script. To do this, both treatment and placebo scripts should begin exactly the same. Only after a targeted voter is identified and marked as having come to the door should the scripts diverge to either treatment or placebo. Accurately marking the voter as having come to the door is essential for the experiment to work properly. We provide a sample placebo script and instructions to canvassers [here](placebo treatment).
- The Design of Field Experiments With Survey Outcomes: A Framework for Selecting More Efficient, Robust, and Ethical Designs describes the design and an application study. This repository assumes knowledge of that paper.
- Durably reducing transphobia was the first published experiment using the design.
- The original field experiments in The Minimal Persuasive Effects of Campaign Contact in General Elections: Evidence from 49 Field Experiments were also conducted using this design.
- Our companion paper Increasing Response Rates and Representativeness of Online Panels Recruited by Mail: Evidence from Experiments in 12 Original Surveys contains recommendations on optimal incentives and anticipated response rates.
Q: If the design is used for a canvass experiment canvassers may need to walk for a small distance between households who answered the survey in order to deliver the treatment. How can this be dealt with?
A: Most subjects targeted with the baseline survey do not participate in it and will not be eligible for treatment. In essence, the baseline survey has served as an oracle that reveals the many houses where, if the canvasser were to visit, their time would be wasted from the point of view of the experiment. We have found that when explaining the reason for low canvass turf density this way, canvassers readily understand that wasted time walking is better than wasted time both walking and talking.
Q: Are response rates lower in battleground states?
A: In data from a national random sample we plan to release soon, we see no differences in response rates between "battleground states" and non-battleground states, at least in March of 2016. This could change closer to election day.