The difference between accessible population and sampling frame lies in the concept of the reachable group versus the actual list or tool used to select participants from that group.
The fundamental difference is that the sampling frame is a specific list or method used to access individuals from the accessible population, which is itself a subset of the larger target population.
Understanding the Population
According to the provided reference, the population is the "all people or objects to which you wishes to generalize the findings of your study". This is your broad target group. For example, if your study focuses on pregnant teenagers, the entire group of pregnant teenagers is your target population.
The Accessible Population
While the reference doesn't explicitly use the term "accessible population," it describes the sampling frame as being derived from "the people or object that you have access to them". This group of people or objects you can access within the larger population constitutes the accessible population. It's the portion of the target population that is within your reach given practical constraints like geography, resources, and time.
The Sampling Frame
The reference states, "Sample frame is a subset of the population and the people or object that you have access to them". The sampling frame is the actual list, register, or method used to identify and select potential participants from the accessible population. It's the operational tool you use for sampling.
For instance, if your target population is all pregnant teenagers (as in the reference example), but you only have access to those attending specific clinics or schools in a particular city (this group would be your accessible population), then a list of pregnant teenagers registered at those specific clinics or schools would be your sampling frame.
Key Differences Summarized
Here's a simple comparison based on the reference's definition:
| Feature | Population | Accessible Population (Implied) | Sampling Frame |
|---|---|---|---|
| Definition | The entire group for generalization. | The portion of the population you can access. | The list or tool used to sample from the accessible group. |
| Reference Info | "all people or objects to which you wishes to generalize" | "the people or object that you have access to them" (part of Sampling Frame definition) | "a subset of the population and the people or object that you have access to them" |
| Relation | The overarching group. | A subset of the Population. | A list or tool derived from the Accessible Population. |
| Purpose | Defines the scope of the study's findings. | Defines the practical reach of the study. | Provides the means to select participants. |
In essence, the accessible population is the group you can reach, while the sampling frame is the list or mechanism you use to select individuals from that reachable group. The sampling frame is ideally a complete and accurate representation of the accessible population.
