Codes and Frequencies
For sample adults, PHQCAT indicates the severity of depressive symptoms based on the responses to questions from the Patient Health Questionnaire (PHQ) depression scale.
The PHQ consists of eight questions that have the same response options. The response options are assigned points (0 for "Not at all," 1 for "Several days," 2 for "More than half the days," and 3 for "Nearly every day") and can be summed to create a total score between 0 and 24 to assess the severity of depressive symptoms.
PHQCAT categorizes the score for the PHQ into four categories: None/Minimal (0-4), Mild (5-9), Moderate (10-14), and Severe (15 or greater). If one question was refused, not ascertained, or answered as don't know, the average of the other seven questions was calculated (as a stand-in for the missing score) and added to the summed total of those seven questions to create a total score. If two or more questions were refused, not ascertained, or answered as don't know, then PHQCAT was coded as not ascertained.
For researchers who want a continuous measure to indicate the severity of depressive symptoms and intend to sum responses to the variables included in the PHQ, IPUMS NHIS assigns codes that are consistent with the PHQ's advised scoring system. 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.
The Patient Health Questionnaire depression scale (PHQ), according to the 2019 Survey Description, "is used in clinical settings and in population-based studies to screen for symptoms indicative of a possible clinically significant depression and assess severity of depressive disorders." PHQ questions that are included as part of the NHIS are:
Over the last two weeks, how often have you been bothered by...
- little interest or pleasure in doing things? (PHQINTR)
- feeling down, depressed, or hopeless? (PHQDEP)
- trouble falling or staying asleep, or sleeping too much? (PHQSLEEP)
- feeling tired or having little energy? (PHQENGY)
- poor appetite or overeating? (PHQEAT)
- feeling bad about yourself, or that you are a failure, or have let yourself or your family down? (PHQBAD)
- trouble concentrating on things, such as reading the newspaper or watching television? (PHQCONC)
- moving or speaking so slowly that other people could have noticed? Or the opposite, being so fidgety or restless that you have been moving around a lot more than usual? (PHQMOVE)
- 2019: Sample adults age 18+.
- 2019 : SAMPWEIGHT