---
url: "https://questionstar.com/principles-of-survey-research/chapter-3/slide-087.html"
title: "\"Which brand of shampoo do you use?\" — what is unclear?"
type: "lehrbuch-slide"
chapter: 3
chapterTitle: "Questionnaire"
slide: 87
---

# "Which brand of shampoo do you use?" — what is unclear?

*Rule 1 · Analysis*

| W | Aspect | Why unclear? |
|------|------|------|
| Who | Reference person | Unclear whether only the respondent themselves or their entire household is meant. |
| What | Reference object | Unclear how to answer if several brands are used. |
| When | Reference period | No reference period given — this morning, this week, or the whole year? |
| Where | Situation / place | At home, at the gym, on vacation, on a business trip? |

---

*Slide 87 of 274 · Chapter 3: Questionnaire · Principles of Survey Research · Dr. Paul Marx*