A total PP score with a range of 0 to 100 will be derived from taking the average of the symptom and sign scores.
Total score can only be derived after deriving the symptoms and signs
Missing values can be determined be using the day variable : e.g., for symptom : To obtain a symptom score on a given day, responses to at least 2 of the 5 questions must be available. If more than 3 questions are missing, the symptom score is considered missing.
For sign : Responses to at least 3 of the 6 questions must be available in order to obtain a sign score for a given day. If more than 3 questions are missing, the sign score is considered missing.
This can be achieved by using the day variable for each ID we have 1-7 days in week 1 and so on... in my original data i have data more than 50 weeks.
On a daily based every ID will answer some questions (11 questions - 5 belongs to symptoms and 6 belongs to signs). if they answer only 1 in symptoms then we will flag them as missing for that particular day.
as per the task :
The PP is an 11-item subject-reported instrument that assesses severity of symptoms and subject observed signs commonly associated in plaque psoriasis. It has been shown to be reliable and valid in measuring symptoms and signs of subjects with moderate-to-severe plaque psoriasis in the clinic and has strong psychometric properties in assessing treatment effects in clinical trials. Subjects are asked to rate the severity of each item on an 11-point Numeric Rating Scale ranging from 0 (absent) to 10 (worst imaginable).
A symptom score will be derived by averaging the 5 questions (i.e., itch, pain, stinging, burning, skin tightness) included in the symptom score and multiplying by 10. To obtain a symptom score on a given day, responses to at least 2 of the 5 questions must be available. If more than 3 questions are missing, the symptom score is considered missing.
A sign score will be derived by averaging the 6 questions (i.e., skin dryness, cracking, scaling, shedding or flaking, redness, bleeding) included in the sign score and multiplying by 10. Responses to at least 3 of the 6 questions must be available in order to obtain a sign score for a given day. If more than 3 questions are missing, the sign score is considered missing.
Both symptom and sign scores range from 0 to 100, where 0 represents the least severe symptom/sign and 100 the most severe.
A total PP score with a range of 0 to 100 will be derived from taking the average of the symptom and sign scores.
Trial administered the PP with a 24-hour recall period on a daily basis. To calculate the scores at each visit, the daily scores with 24-hour recall periods over the prior 7 days will be used and the average score to each of the 11 questions will be used as the score at that visit. In case missing data arise during the 7 days prior to the visit, daily scores of at least 4 days out of the 7 can be used. If greater than 3 scores are missing, the average score will be missing. The baseline PP scores are calculated based on the daily diary collected data during the screening period.
I believe the intermediate table will be averages on a daily basis,
To calculate the scores at each visit, the daily scores with 24-hour recall periods over the prior 7 days will be used and the average score to each of the 11 questions will be used as the score at that visit. In case missing data arise during the 7 days prior to the visit, daily scores of at least 4 days out of the 7 can be used. If greater than 3 scores are missing, the average score will be missing.
This has already been calculated and derived as DAY variable.
