How are one's sleeping habits and quality over the last month?

The Pittsburgh Sleep Quality Index (PSQI) is an instrument used to measure the quality and patterns of sleep in adults. It differentiates “poor” from “good” sleep quality by measuring seven areas (components): subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medications, and daytime dysfunction over the last month. 

Resources:

• Shahid, A., Wilkinson, K., Marcu, S., & Shapiro, C. M. (2011). Pittsburgh Sleep Quality Index (PSQI). – STOP, THAT and One Hundred Other Sleep Scales, 279–283. https://doi.org/10.1007/978-1-4419-9893-4_67

Parameters
This survey cannot be tweaked.


What data is collected? How is it scored?
The following variables are recorded:

• PSQI_1
• PSQI_2
• PSQI_3
• PSQI_4
• PSQI_5
• PSQI_6
• PSQI_7
• PSQI_global_score

Calculation:

PSQI_1: Subjective Sleep Quality
Calculated based on the response to question #6. Scores: "very good" = 0, "fairly good" = 1, "fairly bad" = 2, "very bad" = 3.

PSQI_2: Sleep Latency
Calculated based on responses to questions #2 and #5a.
PSQI_2_1 calculated from question #2:
Scores: 0 if Q2 ≤ 15, 1 if 15 < Q2 ≤ 30, 2 if 30 < Q2 ≤ 60, 3 if Q2 ≥ 60.
PSQI_2_2 calculated from question #5a:
Scores: 0 for "Not during the past month," up to 3 for "Three or more times a week."
Final PSQI_2 calculated by adding PSQI_2_1 and PSQI_2_2 scores:
Scores: 0 if total is 0, 1 if total is 1-2, 2 if total is 3-4, 3 if total is 5 or more.

PSQI_3: Sleep Duration
Calculated based on the response to question #4.
Scores: 0 if Q4 > 7 hours, 1 if 6 < Q4 ≤ 7 hours, 2 if 5 < Q4 ≤ 6 hours, 3 if Q4 < 5 hours.

PSQI_4: Habitual Sleep Efficiency
Calculated based on responses to questions #1, #3, and #4.
sleep_eff calculated as (sleep hours / time in bed) * 100.
Scores: 0 if sleep efficiency ≥ 85%, 1 if 75% ≤ sleep efficiency < 85%, 2 if 65% ≤ sleep efficiency < 75%, 3 if sleep efficiency < 65%.

PSQI_5: Sleep Disturbances
Calculated based on responses to questions #5b-5j.
Sum of scores from questions #5b to #5j, ranging from 0 to 3 for each question.
Scores: 0 if total score is 0, 1 if total score is 1-9, 2 if total score is 10-19, 3 if total score is 20 or more.

PSQI_6: Use of Sleeping Medication
Calculated based on the response to question #7.
Scores: Value of the response.

PSQI_7: Daytime Dysfunction
Calculated based on responses to questions #8 and #9.
Sum of scores from questions #8 and #9, ranging from 0 to 3 for each question.
Scores: 0 if total score is 0, 1 if total score is 1-2, 2 if total score is 3-4, 3 if total score is 5 or more.

PSQI_global_score: Global PSQI Score
Calculated by summing up the component scores PSQI_1 to PSQI_7.