In the past week, we have received several e-mails expressing interest in the NPTS Add-On
program. Many of you have asked us for a cost estimate. Because the next NPTS has not been
designed, nor has contractor(s) selection been made, we cannot quote a price for add-on
samples. However, we can give you some "guesses." Here is a list of common
questions we've received so far, along with answers from Susan Liss (FHWA), and the
rest of the NPTS team.
1. What did it cost in the past?
For the 2001 survey, the cost of an Add-on sample was $165 per completed household.
2. When will we know more about costs?
FHWA has let a Request For Information (RFI) to get projected costs for the next survey
(using the 2001 survey content and approach as a strawman). The RFI was let on 6/24 and
responses are due on 7/24. We expect to contact RFI responders during the month of August
to work out questions and suggestions. We plan to have a much better estimate of survey
costs by Labor Day.
The Request for Information, posted at:
Go to Office of Acquisition Management, Washington DC, click on Posted Dates, then click
on Previous Days, then go to June 24th and click on "Request for Information for
Costs of Conducting the NPTS 01".
3. Why would the costs change from the 2001 survey?
From my experience with the NPTS series, the response
rate is the big driver of costs. Much of the survey resources are devoted to recruiting
households and keeping them involved in the survey through completion. Since we conduct a
telephone survey, we are hopeful that the Do Not Call List (which does not apply to
research surveys) has made the public more amenable to participating in a telephone survey
since they are not being deluged with telemarketer calls.
4. For planning purposes, what number should I use now?
I would use $175 per completed household. BUT, recognize this is my best guess-timate. It
is not an actual cost estimate.
5. Is it possible that the costs will be less than the $165 per household that the add-ons
paid in the 2001 survey?
Yes, it is possible. One of the reasons we let the Request For Information was to see if
we could offer the add-on samples at a lower cost.
6. What if the next NPTS has different content and methods than the survey described in
the Request for Information?
We will need to bear that in mind and make appropriate adjustments as we plan the next
survey. However, we also plan to have enough Add-ons so that a survey very similar to the
2001 could be conducted for you, based on the cost estimates we receive from the RFI.
There is certain core content to a household travel survey that will not change.
7. Is there a minimum sample size?
In the three survey years that add-ons have been conducted (1990, 1995 and 2001), we have
suggested that a minimum sample of 1000 households be conducted for an add-on
8. How can I calculate the appropriate sample size for my jurisdiction?
Appropriate sample size depends on the size of your area, the questions you want answered
by the survey and the degree of statistical validity you need. Nancy McGuckin of the NPTS
Team can help you get a better idea of an appropriate sample size.
Once the survey research firm(s) have been selected for the next NPTS, their sampling
statisticians can work with you on sample size and other sample needs. (No, they don't
try to sell you more samples--- my experience has been that they are annoyingly scientific
about the process.)
9. How can I give my input for the next NPTS survey?
There are several ways -
. Respond to the RFI (see above) - comments and input on all aspects of the next NPTS are
being solicited, in addition to the cost estimates
. Visit to the Community of Practice website for NPTS, where we are establishing a
communications channel with our potential add-ons, other data users and other survey
stakeholders. Go to <http://knowledge.fhwa.dot.gov/cops/hcx.nsf/home> Scroll to the
bottom, and click on "Household Travel Data Program"
. Call or email one of the NPTS Team members
Susan Liss, Project Manager, 202-366-5060, susan.liss(a)fhwa.dot.gov
Nancy McGuckin, Travel Behavior Analyst, 202-366-8750 nancy.mcguckin(a)fhwa.dot.gov (works
on NPTS Tues, Wed afternoon & Thurs.)
Nanda Srinivasan, Travel Data Analyst, User Support & GIS, 202-366-5021
nanda.srinivasan(a)fhwa.dot.gov (yes, this is the same Nanda Srinivasan that also works on
Yuki Nakamoto, SAS Programmer, 202-366-6958 yuki.nakamoto(a)fhwa.dot.gov (works on NPTS on
Tues & Thurs)
Thank you for your interest in the NPTS Add-on Program. Those of us on the NPTS Team
believe the Add-on component is a useful, tested, comprehensive way of obtaining a
household travel dataset for your area.