Split-Frame Sampling

Oftentimes, researchers are faced with the challenging task of targeting rare domains in a population while maintaining the probability-based nature of the employed sample.  For instance, in a national RDD sample it might be necessary to oversample households with small children or those with even less prevalent attributes.  While an epsem sampling design, whereby all numbers have the same chance of selection, will provide the most efficient sample with respect to the precision of survey estimates, from a cost perspective such a design can be completely prohibitive due to the required level of screening for reaching eligible households.  This is where a cleverly designed stratified sampling alternative that employs disproportional allocation can prove highly valuable.

In practice, an optimal sample allocation scheme takes into account the unit cost per interview in each sampling stratum.  As such, a stratum with a high incidence of reaching members of the target population will receive a higher allocation as compared to other strata.  This disproportionate sample allocation should be exercised while providing a non-zero chance of selection for all telephone numbers to ensure a probability-based sample.

The objective of this stratification is to provide a means for over sampling the target populations by segregating higher incidence households into distinct sampling strata.  This is done by matching all numbers against commercial databases, which contain household and individual level demographic data, and identifying the numbers that meet the specified target.

With access to all the top commercial databases Marketing Systems Group can provide cost-effective solutions for sample surveys that aim to target rare domains.  By placing such telephone numbers in the “top” or high incidence stratum and the remaining telephone numbers covering the geography of interest in another, you can create a complete sampling frame.  Subsequently, using an optimization procedure a higher sampling fraction will be determined for the top stratum cognizant of the design effect that will result from a disproportional sample allocation and will need to be adjusted for when weighting.



TCPA Compliance

My name is Tim Antoniewicz and I am not a lawyer.  I am not legal counsel.  I once played Clarence Darrow in a junior High School production of Inherit the Wind but what I am about to say should in no way be considered legal advice.  However it may be considered helpful in sorting out the quandary that many researchers face when conducting research with a cellular sample frame.

In light of the new FCC regulations (6/18/15) that expand the TCPA, CASRO has provided the following guidelines:

The Federal Communications Commission approved new regulations that expand the Telephone Consumer Protection Act (TCPA). The new FCC rules broaden restrictions on autodialed calls to cell phones without differentiation for caller intent. 

ALL calls to cell phones made using an auto-dialer are PROHIBITED.


ALL calls to cell phones should be manually dialed.

Regularly update number databases to identify numbers ported to cell phones.


Use a predictive dialer OR an auto-dialer to call cell phone numbers.

Assume that human proximity to, or intervention in, the placement of an autodialed call to a cell phone provides exemption from the TCPA.

Staying educated and taking proactive measures are the key to compliance with the law. Here are some high-level guidelines to follow:

  • Mitigate the risk by verifying the types of phones numbers on your list
  • Get the consent of the current wireless subscribers to a number
  • Be aware of ethical considerations including respondent safety and privacy.

Marketing Systems Group can assist you in flagging likely wireless numbers, identifying ported landline-to-wireless numbers and real-time screening of active cell phone numbers.

MSG is committed to helping you navigate the ever changing regulation landscape from the TCPA and remain in compliance while accomplishing your research goals.

For more information about TCPA compliance, see http://www.tcpacompliance.us/