Our client is a multinational consumer goods company considering expanding their sachet shampoo line in the Philippines. They want to understand the total annual market size (in units) for sachet shampoo in the country. How would you estimate this?

Situation

I was asked to estimate the annual market size for sachet shampoo in the Philippines during a case interview for a consulting role. The interviewer didn't provide data, so I had to make reasonable assumptions and walk through the logic.

Task

My task was to structure a top-down estimation, breaking the problem into manageable components: population segments, usage frequency, and average sachet consumption per use.

Action

I started by assuming the Philippine population is around 110 million. I segmented by income: roughly 60% belong to the mass market (C-D-E classes) who are the primary sachet users, assuming some from B class also use sachets. That's about 70 million potential users. Then I estimated average washing frequency: Filipinos typically shampoo every other day, so 180 washes per year. Each wash uses about 1 sachet (some use half, but to simplify). Then I multiplied: 70 million * 180 = 12.6 billion sachets per year. I acknowledged this was a rough number and noted that not everyone uses shampoo (some use bar soap), and some might use more than one per wash. I then refined by segmenting: children (0-12 years) might wash daily but use smaller sachets or share, adults (13-60) stick to every other day, seniors often wash less. The refined estimate came out around 8-10 billion sachets. I also discussed what factors could adjust this, like rural vs urban usage patterns, and the shift to bottled shampoo in some segments.

Result

The interviewer seemed satisfied with my structure and willingness to refine assumptions based on feedback. I demonstrated comfort with numbers and logical reasoning, even if the exact number wasn't the goal.