Description

For sample adults, MILKTYPE reports the kind of milk the respondent drank most when drinking milk. This question was asked directly of respondents beginning in 2000; prior to 2000 MILKTYPE is a constructed variable. Constructing MILKTYPE before 2000 allows researchers to compare milk consumption across more samples. Researchers may wish to use MILKTYPE in conjunction with MILKYR, which is a recoded variable that reports the number of times the respondent consumes milk in one year. For more information on how the constructed values of MILKTYPE compare to those generated by the survey question, please see the Survey Text and Comparability tabs.

MILKTYPE is part of a series of variables initiated in 1987 related to food, food knowledge, and cancer.

Comparability

Prior to 2000, respondents were asked to report the frequency with which they drank three different kinds of milk. Beginning in 2000 respondents were instead asked about the frequency for milk in general, then asked about type of milk they typically consumed. Prior to 2000 MILKTYPE uses the recoded frequencies for different types of milk consumed per year to determine which type of milk the respondent drank most often. A response category was created for respondents prior to 2000 for respondents who drank multiple types of milk equally. However, such response categories are not available as part of the samples in which the question was asked directly.

The types of milk available as response categories differ across years. Whole milk and 2% milk are available as response categories in all samples. However, prior to 2000, skim milk, 1% milk, ½% milk, and buttermilk are all included in a single response category. In 2000, response categories include 1% milk, ½% milk, non-fat or skim milk, and "other" in addition to 2% and whole milk. Beginning in 2010, low-fat milk (including 1% and ½%) are condensed into a single response category; other categories include skim or non-fat milk, 2% or reduced-fat milk, whole milk, and other.

Prior to 2000, respondents were asked about foods they usually ate in the past year. Beginning in 2000, this recall period was reduced to foods the respondent usually ate in the past month. The structure of the responses (recording number of times a food was consumed and the time unit associated with that frequency) makes it possible to compare response categories even with different recall periods

Changes in survey design (e.g., quarters in which the supplement was collected) may affect raw frequencies, but do not affect comparability of the variable. As always, data users should use the prescribed IPUMS NHIS weights.

Universe

Availability

• 1987, 1992, 2000, 2010, 2015

Weights

• 1987, 1992, 2000, 2010, 2015 : SAMPWEIGHT