General Documentation

A semi-quantitative food frequency questionnaire (FFQ) has been developed at Harvard University and is available for research purposes. It is the result of over forty years of continued development, evaluation, refinement, and re-evaluation. It was originally created to be used as a paper self-administered, mailed questionnaire. At every step we have attempted to examine the reproducibility and validity of the questionnaire by comparing its estimates with those of diet records or multiple 24-hour recalls and with relevant biochemical indicators of nutrient intakes.  Such studies have been conducted among adults of all ages and both sexes, and among a variety of socioeconomic groups; many of these validation studies have been published. The results of the validation studies have indicated that the method is remarkably robust; similarly valid results have been obtained from virtually all the groups that we have studied. Obviously, the process of continued refinement of the questionnaire can not stop, in part because the nature of the food supply and the distribution of dietary intakes is in constant change.

While the semi-quantitative FFQ was developed for our own research purposes, we are happy to share it with other investigators. This extended use has obvious advantages in better defining the useful scope and limits of the methodology, and, sometimes, providing direct information on the degree of validity in different populations and with various methods of administration.

Although we are not organized as a service group, we have tried to accommodate the wide variety of requests from different investigators as efficiently as possible and within the limited constraints of research budgets. For routine questionnaire processing, this operates quite smoothly at present. Most importantly, we have strived to maintain the same level of data quality for external users, as we want for our own research. It is our hope to be able to provide a REDCAP questionnaire soon for investigators preferring to use an online questionnaire in their study. Details will be forthcoming.

We have developed this website for those interested in obtaining copies of the food frequency questionnaires. Due to the volume of investigators interested in receiving the questionnaires, we ask you to please review the information on this website to answer general questions. PLEASE NOTE: ANY SALE OR COMMERCIAL USE OF THE QUESTIONNAIRE REQUIRES WRITTEN PERMISSION OF OUR INSTITUTION.

Downloads

Frequently Asked Questions

Completing the FFQs

How should the participants fill out the FFQ?

The questionnaire should be coded in a #2 pencil with bubbles filled in completely. The scanner will not detect partially filled bubbles or pen. This does not apply to questions that are left blank by the participant, these can remain.

On average, how long does it take a participant to complete the FFQ?

The questionnaire usually takes approximately 20 minutes to complete.

How should my questionnaires look upon return for processing?

Each questionnaire should be completed using a number two pencil. Please refrain from placing labels, holes, stray marks, staples, paperclips or names on each questionnaire. Each questionnaire must be assigned an identification number to be analyzed. Due to HIPPA regulations, any questionnaire received with personal identification such as a name or social security number will be returned to the investigator. If this information is already on your questionnaire, the identifying information must be crossed out or erased before submitting for processing so that it is not visible. Before submitting FFQs for analysis, review to confirm questionnaires are filled out correctly. Any submitted with incorrect markings will be sent back for review at your expense.

How should I assign an identification number?

Each questionnaire requires an ID number before it can be scanned and analyzed. You may choose unique numbers that have 8 or less digits. Double check that duplicate IDs were not assigned. Please take into account the size of your study and any follow-up studies that may follow when assigning IDs. The ID needs only to be meaningful to the investigator. You do not need to assign leading nor trailing zeros.

Does the Harvard T.H. Chan School of Public Health provide instruction for participants or investigators?

We do not provide the study coordinators with any instructions when administering food frequency questionnaires to participants. But the following Coding Instructions must be followed.

An optical scanner is used to read the bar codes and the “skunk marks” along the border of the SFFQ, as well as the coding bubbles within the body of the SFFQ. Users of the SFFQ must use only a NO. 2 PENCIL or a NO.1 PENCIL to mark the questionnaire. The scanner will not recognize ink whether black or blue ink. If the respondent completes the questionnaire in ink, the responses must be shaded over with pencil.
When the machine reads a page, it reads both sides of the page simultaneously. For this reason, care must be taken to avoid writing text on top of any bubble or black rectangle on any page. The scanner sees double responses if writing over bubbles exist. If lead covers the black rectangles or is present in between the black rectangles, the questionnaire will not scan. Studies will be responsible for “cleaning up” these errors by transcribing the SFFQ over onto new forms. To best avoid this possibility, writing, whether in ink or pencil, is only allowed in blank white margins found on any questionnaire.
Additionally, NEVER WRITE OR PLACE LABELS above the solid bar at the top of each page. This will interfere with the bar code. If labels must be added onto the questionnaires, keep them very small and carefully place them only on the top center of page 1, where it reads “dietary assessment” without covering any coding bubbles (the box that is shaded blue). If the label is placed too high on the SFFQ, the questionnaire will eject out of the side of the scanner. IF the label crosses the box outlining question 2 on the SFFQ the scanner will pick up 6+ per day responses on the fruit and vegetable section on page 2.
Again, do not add scotch tape, staples, paperclips or punch holes to any part of the SFFQ, or submit questionnaires that are damaged (either wrinkled or torn). All scenarios often cause the questionnaire to enter the scanner at an incorrect angle or become jammed and torn within the scanner, further damaging the questionnaire. Again, studies will be responsible for correcting these errors which may entail copying SFFQs over to blank forms.
Finally, if self-coded, the SFFQ needs to be “scanner ready”. Please separate each booklet along their perforation before mailing them in for analysis. Also, please bundle the SFFQs together in an elastic band. Do NOT paper clip individual questionnaires. You may clip the SFFQ batch depending on the size of the batch.

If you have any questions concerning the completion of the SFFQ, please contact Laura Sampson at lsampson@hsph.harvard.edu. We suggest that you send a copy of your questionnaires to Laura Sampson for approval if you make any written changes or label additions to the questionnaire before utilizing in your study. If adherence to the above guidelines are not followed correctly, investigators need to expect additional processing fees.

Mailing and payment

Where should I send the questionnaire to be analyzed?

SUBMIT YOUR ORDER FORM WITH EACH BATCH OF QUESTIONNAIRES SUBMITTED FOR PROCESSING.

All questionnaires should be sent to:

Harvard T.H. Chan School of Public Health
Nutrition Department, Bldg. 2, 3rd Floor, Room 310
ATTN: Vanessa Beauregard, NQSC
665 Huntington Ave.
Boston, MA 02115

Where should I send payment for FFQs or processing?

Harvard T.H. Chan School of Public Health
Nutrition Department-Finance
ATTN: Bristian Justice
Bldg.2, 3rd floor
665 Huntington Ave.
Boston, MA 02115

Please make sure payments include in the memo “NQSC (Invoice #); B.Justice 2-7866” as an identifier. Wire transfer is preferred for orders over $1000.00. Please contact Bristian Justice for wire transfers and internal payments; phone: 617-432-7866 or bjustice@hsph.harvard.edu. For billing questions, please contact Lauren Dougherty at 617-998-6615 or lwolfert@hsph.harvard.edu.

When will my institution receive an invoice?

Invoices are sent for the cost of blank questionnaires and then again once processing has been completed and you have received your data. Please provide purchase orders to cover costs for each. We accept payments by check, wire transfer, or Harvard Internal Payments (Harvard Affiliates Only). We do not accept credit cards.

WinZip files and access

What type of output will I receive and how will I receive it?

You may also choose to have your scanned and nutrient output data files returned so that you can do additional statistical testing. You may choose either ASCII or EXCEL format for these files. Your data will be sent electronically via a WinZip file attachment. Your questionnaires will be returned via FedEx. Please remember to include TWO email addresses on the billing form, which can be obtained from the website.

How do I get WinZipped files?

The WinZip file is sent using Harvard’s FileZilla Secure Transfer. You must login and pick up your data within 10 days. Please provide two email addresses for receipt of the WinZip files to assure data is obtained within the specified time.

If you do not have WinZip, you can go to winzip.com. There is an evaluation program that you can download and programs to purchase that will open WinZip attachments.

How do I open the contents of the WinZip attachments if I do not have WinZip?

Download 7-Zip file manager, for free online.

To open csv.label files, use notepad and to open the rawlogs and score files use Microsoft Word.

Please work with your IT Department if you have trouble opening the WinZip attachment.

Calculating servings

How do I calculate the number of servings of fruits or vegetables per day?

If you would like to calculate the number of servings of any food grouping, you must sum the daily frequencies reported for the foods you select to represent your group. The frequency weights for the 2022 Grid (grid2022) are listed below.

Example: grid2022 servings of fruit per day
Participant reports:

Bananas 1-3 per month
Cantaloupe 1 per day
Orange 2-4 per week
Other fruit juices 2-3 times per day

Frequency factors:
Bananas – 0.08
Cantaloupe – 1.0
Oranges – 0.43
Other fruit juices – 2.5

Sum frequency factors: 0.08 + 1.0 + 0.43 + 2.5 = 4.01 servings per day of fruits

*********************Grid2022 frequency factors:******************************

ffwgt0 0; never (default for no answer)

ffwgt1 0.08; 1-3/mo

ffwgt2 0.14; 1/wk

ffwgt3 0.43; 2-4/wk

ffwgt4 0.8; 5-6/wk

ffwgt5 1; 1/day

ffwgt6 2.5; 2-3/day

ffwgt7 4.5; 4-5/day

ffwgt8 6; 6/day

ffwgt9 0; passthru

Self-coders and/or editors

What is a self coder and a self coder/editor?

A self-coder is responsible for coding the study participant’s ID in the appropriate box and filling in codes related to open-ended questions. Each self-coder will receive a coding manual, which explains the procedure, along with codes for margarines, oils, vitamins, cereals and foods. A self-coder/editor is responsible for the self-coding duties, editing the scanned data and returning edited outputs and questionnaires to Laura Sampson for completion of analysis. The editing process usually requires dual mailing.

PERMISSION MUST BE OBTAINED TO QUALIFY AS A SELF-CODER AND/OR EDITOR. CONTACT LAURA SAMPSON AT: (lsampson@hsph.harvard.edu)

What constitutes a large study to be eligible for self-coding?

For studies to be eligible for self-coding they need to have 1000+ study participants.

If I am authorized to be a self-coder or self-coder/editor, can I obtain instructions for these duties?

View the General notes for Adults’ Semiquantitative Food Frequency Questionnaire.

Validation articles and nutrient database reference

What are the published validation articles?

Al-Shaar, L., Yuan, C., Rosner, B., Dean, S. B., Ivey, K. L., Clowry, C. M., … & Rimm, E. B. (2021). Reproducibility and validity of a semiquantitative food frequency questionnaire in men assessed by multiple methods. American journal of epidemiology, 190(6), 1122-1132. [PubMed: https://pubmed.ncbi.nlm.nih.gov/33350436/]

Yuan, C., Spiegelman, D., Rimm, E. B., Rosner, B. A., Stampfer, M. J., Barnett, J. B., … & Willett, W. C. (2018). Relative validity of nutrient intakes assessed by questionnaire, 24-hour recalls, and diet records as compared with urinary recovery and plasma concentration biomarkers: findings for women. American journal of epidemiology, 187(5), 1051-1063. [PubMed: https://pubmed.ncbi.nlm.nih.gov/29036411/]

Yuan, C., Spiegelman, D., Rimm, E. B., Rosner, B. A., Stampfer, M. J., Barnett, J. B., … & Willett, W. C. (2017). Validity of a dietary questionnaire assessed by comparison with multiple weighed dietary records or 24-hour recalls. American journal of epidemiology, 185(7), 570-584. [PubMed: https://pubmed.ncbi.nlm.nih.gov/28338828/]

Michaud, D. S., Giovannucci, E. L., Ascherio, A., Rimm, E. B., Forman, M. R., Sampson, L., & Willett, W. C. (1998). Associations of plasma carotenoid concentrations and dietary intake of specific carotenoids in samples of two prospective cohort studies using a new carotenoid database. Cancer Epidemiology and Prevention Biomarkers, 7(4), 283-290. [PubMed: https://pubmed.ncbi.nlm.nih.gov/9568782/]

Rimm, E. B., Giovannucci, E. L., Stampfer, M. J., Colditz, G. A., Litin, L. B., & Willett, W. C. (1992). Reproducibility and validity of an expanded self-administered semiquantitative food frequency questionnaire among male health professionals. American journal of epidemiology, 135(10), 1114-1126. [PubMed: https://pubmed.ncbi.nlm.nih.gov/1632423/]

Willett, W. C., Sampson, L., Browne, M. L., Stampfer, M. J., Rosner, B., Hennekens, C. H., & Speizer, F. E. (1988). The use of a self-administered questionnaire to assess diet four years in the past. American journal of epidemiology, 127(1), 188-199. [PubMed: https://pubmed.ncbi.nlm.nih.gov/3337073/]

Willett, W. C., Sampson, L., Stampfer, M. J., Rosner, B., Bain, C., Witschi, J., … & Speizer, F. E. (1985). Reproducibility and validity of a semiquantitative food frequency questionnaire. American journal of epidemiology, 122(1), 51-65. [PubMed: https://pubmed.ncbi.nlm.nih.gov/4014201/]

How do I reference the questionnaire for my publication?

Please refer to the *archived file you received in your WINZIPPED data file. Find the date associated with foods.dat.<date>.

Use Harvard SQFFQ.<date>