Kessler's instrument asks how often, during the past 30 days, the respondent felt:

• So sad that nothing could cheer you up? (ASAD)

• Nervous? (ANERVOUS)

• Restless or fidgety? (ARESTLESS)

• Hopeless? (AHOPELESS)

• That everything was an effort? (AEFFORT)

• Worthless? (AWORTHLESS)

As noted above, acceptable responses fell into five categories, ranging from "none of the time" to "all of the time."

Kessler recommends scoring the scale by assigning 0 to 4 points for each of these six questions, based on the reported frequency of the feelings (i.e., 0 for "none of the time"; 1 for "a little of the time"; 2 for "some of the time"; 3 for "most of the time"; and 4 for "all of the time"). The range for summed responses on the K6 Scale is thus 0 to 24, with 0 suggesting the lowest level of nonspecific psychological distress, and 24 suggesting the highest level of nonspecific psychological distress. According to the scoring criteria proposed by Kessler, persons with a score of 13 or greater are likely to be experiencing severe mental illness.

To assist researchers who intend to sum responses to the variables included in the K6 Scale, IPUMS NHIS assigns codes that are consistent with Kessler's advised scoring system (i.e., with "none of the time" coded as 0 and "all of the time" coded as 4). To produce valid results, users must exclude not in universe cases (persons other than sample adults, code 6 in IPUMS NHIS) and unknown cases (codes 7, 8, and 9 in IPUMS NHIS) before summing the responses.

In 2021, a dichotomous variable (PDISTRESSK6) was introduced to record whether a respondent's summed K6 score fell above or below the 13-point threshold for significant psychological distress.

As a follow-up to the K6 Scale questions, the NHIS included a question that was not part of Kessler's original survey instrument. All sample adults who answered "some of the time," "most of the time," or "all of the time" to any of the six questions included in the Kessler 6 Scale were asked, "Altogether, how much did these feelings interfere with your life or activities: a lot, some, a little, or not at all?" (AFEELINT1MO). In 1999, additional follow-up questions collected further information about how "these feelings" affected the person (see FBADHOWOFT, FBADMORE, FBADLESS, FBADUNABLE, and FBADCUTDOWN).