The ABCs of ABS: Why the Address Based Sampling frame works so well

The past 10 to 15 years have been very good to Address Based Sampling (ABS). ABS has grown so much that it is now perceived as a substitute to random-digit-dial dual frame sample designs, and arguably, it has become the dominant sample survey design in the USA.

ABS is a special type of sampling frame, distinguishable from telephone surveys in its flexibility. The frame can support many methods and modalities: web, phone, and mail. In this article we will briefly explore the popularity of ABS and the problems it attempts to solve.

First, a quick historical lesson. Let’s look at what has happened to traditional telephone surveys. Response rates have tanked and many households have scrapped their land lines, forcing survey designers to sample both land lines and cell phone frames. To be fair, as recently as the late 2000’s telephone surveys were still doing rather well. They were still cost efficient and dual-frame survey designs (landline and cell phone) were gaining traction. While it is true that response rates were already in decline, data quality was not suffering.

The picture has changed in ten years. Telephone response rates have continued their precipitous decline (now down into the single digits) and associated risks of systematic bias have risen. Researchers have been forced to adapt by choosing alternative methods without sacrificing sampling integrity. ABS is a countermeasure for the trends we have witnessed with telephone response rates. The costs of telephone surveys have risen as well, compared to ABS. Not only has ABS solved some of those problems, it has opened the door to mixed modes of contact and data collection.

ABS from the ground up

The foundation of Address Based Sampling (ABS) is the United States Postal Service USPS Delivery Sequence File. Marketing Systems Group was one of the first companies to get approval for providing the Computerized Delivery Sequence (CDS) File, which contains just about every deliverable postal address. That’s more than 135 million residential addresses to date.

ABS merges the CDS with other data sources that contain geographic and demographic data. This is like cranking up the volume on your guitar amplifier to “11”. Data sources consist of both publicly available sources such as the Government’s American Community Survey, the Current Population Survey and decennial Census data. Beyond that, ABS can mine commercial databases for additional data.  You can append demographics such as age, gender, income, education, and more. By meshing data sources together, the odds for positive matches are increased and the negative impact of coverage lapses are decreased.  By targeting the household instead of the telephone number, ABS avoids the under and over coverage downside risks of telephone samples.

The difference maker: Geocoding.

Geocoding is the key ingredient which effectively launched ABS as a valid alternative. Geocoding is the application of geographical coordinates to a corresponding postal address location. Why does this matter so much? It means researchers can reach the majority of U.S. households more inexpensively and faster than ever before.

The basic geocoding method works like this:  addresses are coded using linear interpolation, constructing geographical data points within each street segment based on the numeric addresses as end points.  The interpolation is accurate to the street level but not necessarily to the actual rooftop level due to factors such as property size and park spaces. Still, you can get very accurate correspondences with geocoding.

There is no better approach for standard mail surveys as ABS has also solved problems with respect to in-person household surveys. Because CDS does not include census geography, it was a problem to design samples for in-person households. In the old days this was solved through costly methods: multi-stage sampling of primary and secondary sampling units based on census blocks and field-testing every address in a segment. ABS removes those obstacles. Every address is geocoded to a census block, with some exceptions such as P.O. boxes, rural routes, and simplified addresses (rural routes, P.O. boxes with no physical address). While it is true that simplified addresses are a nagging problem –the good news is that the scope of the problem has diminished: the number of simplified addresses, once upwards of 10 million addresses, has been reduced to the hundreds of thousands. Not insignificant, but a vast improvement.

In the past, ABS was hampered by some systematic nonresponse factors. For instance, ABS respondents were more likely to be college grads and less likely to be non-White, as compared to RDD samples. Lately however, mitigation efforts have made real progress due to Census data appends that can be used to predict areas of high nonresponse. You can oversample areas that tend to respond less frequently to ABS surveys. Consumer data also can be appended based on trackable behaviors and predictive models. This too can be used for oversampling nonresponsive areas.  In short, there are fewer reservations attached to the use of ABS, hence its increasing popularity.

ABS isn’t just a “one-trick pony”

To appreciate the raw power of ABS, you need to think of it as much more than its source USPS CDS file. It is an enhancement of it: CDS plus demographics plus geocoding. The effect is empowering. Researchers can increase the range of analysis options for testing hypotheses and models. And the ease of use has fueled the use of multimode surveys to combat the telephone survey problems mentioned above. ABS is also useful for probability-based panel recruitment, non-response follow ups, and for reaching more inaccessible populations with stratified samples. ABS gives you that flexibility. Samples can be drawn to custom specifications without sacrificing representation.

Key Advantages of ABS

  • Single frame. Does away with dual-frame uncertainty.
  • Expansive coverage.
  • Straightforward weighting protocols.
  • Higher response rates, especially when multimodes are used.
  • More precise.

For all the reasons mentioned above, ABS is proving to be the best balance between coverage and cost for many researchers, but we can only outline the many factors involved in a short blog article.

Call MSG today to discuss how ABS can be a difference maker in your survey research.

 

The Power of Conversation

Observers of the market research industry have been noticing a trend of late: researchers are acknowledging the limitations of large-scale surveys and are rediscovering the value of qualitative research, namely, real conversations with real people. Why?

That’s precisely the question, and also, the answer. “Why.” Quantitative research often has difficulty answering the “why?” questions. While it is true that much insight can be gained by analyzing big data, why not go directly to the source and talk to them? By interviewing and hearing people’s stories and insights, you can understand data better. Why do products sell? Why is growth not taking off? Why do preferences emerge for one brand and not another? Some answers are more readily gained by simply talking to people, then interpreting the results.

Continue reading “The Power of Conversation”

Why Location Continues to be a Difference Maker

Last Christmas I wanted to buy a turntable for my daughter. Thanks to an online message forum, I discovered that Target was selling a new brand of turntable at an affordable price point with features typically seen on higher-end models. It was early in the Christmas buying season, and I had a hunch that a product like this might sell out quickly. So I researched the Target.com website, checked their inventory and used the store locator to find the nearest Target with the turntable in stock. At this point many would click the “buy now” button and have the product shipped. Instead, I hopped in the car and drove to the store. Why, you ask? I wanted to see the product for myself before buying it. Once inside the store, my smart phone told me which aisle to go to. With a little help from my friend the store clerk, I located the turntable, looked it over, bought it, and wrapped it up for Christmas. What this very short story teaches us is that while technology has become a key component in the way we consume, we aren’t quite willing to let go of location-based purchasing decisions. Continue reading “Why Location Continues to be a Difference Maker”

County Level Cell Phone Only Estimates

Probability based telephone surveys must utilize a dual frame approach in order to capture the ever increasing cell phone only population.   Until the day comes where it’ll be a single frame approach of only cellular numbers, researchers need to ensure they get the appropriate blend of cell only vs. dual phone users in their sampling allocations. Continue reading “County Level Cell Phone Only Estimates”

Quality Starts with Survey Design: Tips for Better Surveys

Marketing researchers are all facing two important challenges to data quality. First is the question of representativeness: with response rates plummeting, we need to make surveys shorter, more engaging, and easier for respondents to complete. Second is the issue of data accuracy: we must make sure that survey questions measure what we think they measure. Continue reading “Quality Starts with Survey Design: Tips for Better Surveys”

Smart Survey Design: 3 Forgotten Pain Points to Avoid

“Smart Survey Design” is a loose term (bordering on a catch-all) that you’ve probably heard pitched to you.  Maybe you have used it yourself when piecing together a study.

It’s not a hollow term, by any means. Smart design has advantages for both designers and respondents. Designing “smart” simply means maintaining data integrity, both in terms of capturing statistically relevant data as well as reducing the amount of bad data caused by poor survey takers (straight liners, short responders for OE’s, speeders, cheaters, etc.). Continue reading “Smart Survey Design: 3 Forgotten Pain Points to Avoid”

How I Learned to Love AAPOR’s ResearchHack 3.0

It was my first year attending the American Association for Public Opinion Research (AAPOR) Annual Conference, and I was feeling a little nervous. AAPOR is one of the most influential conferences in the survey industry. My goal was to actively participate in events and networking opportunities on the conference list. ResearchHack 3.0 was one of them.

ResearchHack is AAPOR’s version of a “hackathon”, where teams of participants (aka. “hackers”) were asked to devise a plan for a mobile app that would inform various uses of the Census Planning Database. Continue reading “How I Learned to Love AAPOR’s ResearchHack 3.0”

Taking Aim with Consumer Cellular Sample

How Consumer Cellular Sample Can Give You a More Accurate Geographic Fit of your Target Population and Improve Coverage

Geo-targeting. We all know what it means, but for the sake of this article, let’s get at the essence of the concept. Geo-targeting is a way to pinpoint an audience based on location. Accuracy is everything. Geography is the fundamental basis for every sample frame – be it individual streets, Census geography or Postal geography. Continue reading “Taking Aim with Consumer Cellular Sample”

Why Volunteer?

The research industry needs volunteers. Here’s why you should consider playing a part.

Many of us here at MSG serve as active volunteer members of market and survey research industry organizations. It’s part of our company culture to get involved and make a difference. Recently, I attended back to back chapter events, and I began to reflect on the benefits of volunteering. Was it really worthwhile to devote my time to a local chapter organization? Continue reading “Why Volunteer?”