If you ask someone who is dissatisfied or unhappy your customer satisfaction score goes down the toilet. So try and ask only those who will give you a positive result.
Therefore you must segment your customers
In any customer base there will always be
- Segment 1) those who will always give you a high score.
- Segment 2) those who will always give you a low score.
- Segment 3) those who will always tell the truth and score accurately. Normally the largest number of your customers will fall in this segment.
- Segment 4) those who don't like to give low scores in surveys and always give higher marks than you deserve.
Unfortunately if your organisation is really bad at satisfying your customers, the Local Government Ombudsman is a good example, even segmenting, selecting and filtering the survey participants may still not be enough to prevent a really bad result.
The downside of survey participant segmenting, selecting and filtering is that you may be exposed for using such devious tactics which will, as it has done with the Local Government Ombudsman, flush the reputation of your organisation further down the toilet than it already is.