In approach 2 inside the option 3 of this credit we had some uncertainties on how we could proceed with the survey and sampling process. We have set a list of questions which is shown below:
1) This project has two towers in the same site boundary. We would like to know if it is possible to estimate our sample size considering both as a single building, or if it’s necessary to do one sample size for each tower.
2) About the survey timing, do we have mandatorily to do the survey from Monday to Friday, isn’t it possible to do it, for example, from Wednesday to Tuesday? Is there any problem if we have a weekend in the middle of the five consecutive workdays?
3) Performing the survey according to the proceedings, developing it each day or at the conclusion of five consecutive days, is it possible to extend the period of survey into twenty days? If not, do we have to interview all the building´s employees in only one week? For example: we could interview 25% of the employees in the first week, more 25% in the next week and so on.
4) About the methodology for the choice of a determinate sample of respondents, can we establish a random sampling based on a list of employees chosen randomly at the moment of the survey, without a predetermined list? In case of absent of a previous determined employee, how should we proceed?
5) If we develop a survey each day over five consecutive workdays, what are we supposed to do if some employee is absent after answering in some of the days? How can we represent this lack of information?
Dan Ackerstein
PrincipalAckerstein Sustainability, LLC
LEEDuser Expert
819 thumbs up
February 15, 2011 - 4:34 pm
I would suggest a different model for conducting the survey than the one you are proposing. Your question suggests that your team plans to interview building occupants at the end of each day in a 5 day period. While that is certainly a marvelous approach to getting highly reliable data, it is more than EBOM requires. Most SSc4 surveys are conducted on a SINGLE day, asking respondents to describe their commuting behavior over the preceding 5 day period. In applying that model to some of your questions:
2) If there is a compelling reason for to include a weekend, it is probably fine but the intent here is to survey folks in a way that is most likely to get accurate information. The longer in the past a given day's commute was, the less likely that information is to be accurate.
3) Assuming you could survey during a set of weeks very close together, and that you have clearly discrete building subpopulations to survey (to ensure no respondents are being surveyed twice), this is also technically probably ok. Again, a reviewer would want to understand why this deviation from the norm was important, but if your reason is convincing, I think it would be OK.
4) Yes - a list of employees at some point in the survey development process will be fine. Your list should include enough surplus respondents to that you have replacements for employees who are absent or otherwise unable to respond.
5) Absent employees should not be included in the survey sample if they are absent throughout the 5-day survey period - they are simply not commuters that week. If you need to include an employee who is absent one day of the five, you'd have to count that person as a 4/5th employee, as you can't count their absentee day as either a conventional or alternative commute - therefore you have to discount the employee themself. That one's thorny!
And finally, to Question 1 - this really comes down to your LEED project boundary. If you are talking about a single LEED project, then the sample size can be from both towers; if these are separate LEED projects, then each one needs to hit the threshold as individual projects.
Hope that helps
Dan