Examples of using Non-probability samples in English and their translations into Bengali
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Not all non-probability samples are the same.
Bit By Bit- Asking questions- 3.4.2 Non-probability samples: weighting.
Further, non-probability samples are substantially cheaper.
Now, I will show how that same idea can be applied to non-probability samples.
First, unadjusted non-probability samples can lead to bad estimates;
Second, there have been many developments in the collection and analysis of non-probability samples.
First, unadjusted non-probability samples can lead to bad estimates;
In the same way that researchers weight responses from probability samples, they can also weight responses from non-probability samples.
Probability samples and non-probability samples are not that different in practice;
When there are high rates of non-response(as there are in real surveys now), the actual probability of inclusions for respondents are not known, and thus,probability samples and non-probability samples are not as different as many researchers believe.
Non-probability samples need not automatically lead to something like the Literary Digest fiasco.
Bit By Bit- Asking questions- 3.4.3 Non-probability samples: sample matching.
With non-probability samples, weights can undo distortions caused by the assumed sampling process.
One possible reason for these differences is that non-probability samples have improved over time.
On the other hand, weighting non-probability samples will only produce unbiased estimates for all traits if the response propensities are the same for everyone in each group.
Looking forward, I expect that estimates from well-done non-probability samples will become cheaper and better.
As I said earlier, non-probability samples are viewed with great skepticism by social scientists, in part because of their role in some of the most embarrassing failures in the early days of survey research.
Again, this is another example of the dangers of raw, unadjusted non-probability samples and is reminiscent of the Literary Digest fiasco.
Both non-probability samples and probability samples vary in their quality, and currently it is likely the case that most estimates from probability samples are more trustworthy than estimates from non-probability samples.
Unfortunately, when working with non-probability samples, we don't know how the sample was selected.
Again, this is another example of the dangers of raw, unadjusted non-probability samples and is reminiscent of the Literary Digest fiasco.
But, it does mean that when comparing non-probability samples to probability samples in practice, we must keep in mind that both depend on assumptions and auxiliary information in order to produce estimates.
This headline was based in part on estimates from non-probability samples(Mosteller 1949; Bean 1950; Freedman, Pisani, and Purves 2007).
However, the second lesson is that non-probability samples, when weighted properly, can actually produce quite good estimates.
This framework enables us to understand new approaches to representation-in particular, non-probability samples(section 3.4)- and new approaches to measurement- in particular, new ways of asking questions to respondents(section 3.5).
For a meta-analysis on the effect of weighting to reduce bias in non-probability samples, see Table 2.4 in Tourangeau, Conrad, and Couper(2013), which leads the authors to conclude“adjustments seem to be useful but fallible corrections…”.
In conclusion,social scientists and statisticians are incredibly skeptical of inferences from these non-probability samples, in part because they are associated with some embarrassing failures of survey research such as the Literary Digest poll.
But, even now, estimates from well-conducted non-probability samples are probably better than estimates from poorly-conducted probability samples. .
One thing that is clear, however,is if you are forced to work with non-probability samples, then there is strong reason to believe that adjusted estimates will be better than non-adjusted estimates.
Sometimes researchers have found that probability samples and non-probability samples yield estimates of similar quality(Ansolabehere and Schaffner 2014), but other comparisons have found that non-probability samples do worse(Malhotra and Krosnick 2007; Yeager et al. 2011).