Question

A learning lab has commissioned you to administer a survey of people with dyslexia. You will use snowball sampling.

1. Explain how you would select the sample.

2. Explain how you would gather the data.

Answer 1

1. Selecting the Sample:

We need to find a primary data source/s nominating another potential primary data source/s to be used in the research.

1. Linear snowball sampling.

We start with only one person and this person provides only one referral. The referral is recruited into the sample group and he/she also provides only one new referral. This pattern is continued until the sample group is fully formed.

2. Exponential non-discriminative snowball sampling.

The first person that we recruit to the sample group provides multiple referrals and each new referral is explored until primary data from sufficient amount of people are collected.

3. Exponential discriminative snowball sampling.

The people give multiple referrals, however, only one new person is recruited among them. The choice of a new person is guided by the aim and objectives of the study.

2. Gathering Data:

1. Establish a contact with one or two people suffering from dyslexia or relatives/family members of the person suffering from dyslexia.
2. Request those people to identify more such people
3. Ask new people to identify further cases (and so on)
4. Stop when:

a) The pre-specified sample size has been completed;

b) There are no further cases left;

c) Pursuing further cases will make the project unmanageable due to the large size.