TurkPrime is announcing a change in our pricing for the MicroBatch feature. MicroBatch is now included as a Pro feature, with a fee of 2 cents + 5% per complete. This will also provide users with access to all other pro features, with no additional charge. This change is necessary so that we can continue to provide the highest quality service and tools that our users expect.
Some workers on MTurk are extremely active, and take the majority of posted HITs. This can lead to many issues, some of which are outlined in our previous post. Although MTurk has over 100,000 workers who take surveys each year, and around 25,000 who take surveys each month, you are much more likely to recruit highly active workers who take a majority of HITs. About 1,000 workers (1% of workers) take 21% of the HITs. About 10,000 workers (10% of workers) take 74% of all HITs.
It is important to consider how many highly experienced workers there are on Mechanical Turk. As discussed in previous posts, there is a population pool of active workers in the thousands, but this is far from exhaustible. A small group of workers take a very large number of HITs posted to MTurk, and these workers are very experienced and have seen measures commonly used in the social and behavioral sciences. Research has shown that when participants are repeatedly exposed to the same measures, this can have negative effects on data collection, changing the way workers perform, creating treatment effects, giving participants insight into the purpose of some studies, and in some cases impact effect sizes of experimental manipulations. This issue is referred to as non-naivete (Chandler, 2014; Chandler, 2016).
The internet has the reputation of being a place where people can hide in anonymity, and present as being very different people than who they actually are. Is this a problem on Mechanical Turk? Is the self-reported information provided by Mechanical Turk workers reliable? These are important questions which have been addressed with several different methods. Researchers have examined a) consistency of responding to the same questions over time and across studies b) the validity of responses, or the degree to which the items capture responses that represent the truth from participants. It turns out that there are certain situations in which MTurk workers are likely to lie, but they are who they say they are in almost all cases.
Hundreds of academic papers are published each year using data collected through Mechanical Turk. Researchers have gravitated to Mechanical Turk primarily because it provides high quality data quickly and affordably. However, Mechanical Turk has strengths and weaknesses as a platform for data collection. While Mechanical Turk has revolutionized data collection, it is by no means a perfect platform. Some of the major strengths and limitations of MTurk are summarized below.
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Many researchers wish to target participants from specific states or regions of the United States like the Northeast or the West. The problem they often encounter is that using MTurk's Geographic Qualification to specify a particular state is often not adequate to ensure participants actually reside in the specified state.
What is the completion rate and dropout rate?
Dropout rate is defined as the percentage of participants who start taking a study but do not complete it. Dropout rate is sometimes referred to as attrition rate, and is the opposite of completion rate (dropout rate = 100 – completion rate). On MTurk, completion rate is defined as the number of Workers who submit a HIT divided by the number of Workers who accept the HIT. Note that, for the definition of completion rate used here, Rejected Workers are counted as completes.
Requesters may observe that some workers, even those with high Approval ratings, may not perform to their expectations on a study. Sometimes this may result in rejecting their work which affects the Worker approval rating. But, often the work is not acceptable for research but is not worthy of rejection, or, it may simply be the policy of the research lab to approve all assignments for IRB or some ethical standard they may follow.
You are running a longitudinal study and have identified 1000 workers who you want to allow to take your second phase studies. How do you easily group those workers for easy access.
Or you want to exclude certain workers from taking a number of your studies and wish to group them for easy exclusion in future studies. How can you do that?