Sampling Protocol

The sampling protocol is the procedure used to select units from the study population to be measured. The goal of the sampling protocol is to select units that are representative of the study population with respect to the attribute(s) of interest. The sampling protocol deals with how and when units are selected.

Let’s look at our research question: How much time does the male osprey incubate the eggs relative to the female?  To answer that question, we need to measure the amount of time that Hal is incubating the eggs compared to Harriet. Our sampling unit is, thus, time. We can’t possibly watch the birds all day and night, so we will sample units of time to determine and record which bird is incubating.

Our units of time must be representative of the study population. We suspect that birds, like humans, have daily habits that could influence which bird is incubating. This means we will need to spread out our time samples throughout the day. To ensure time samples are not influenced by our own daily habits, we randomly select times within the restrictions of the schools’ available viewing hours.

A random selection is not predictable and relies only on chance. This is important, because if the birds’ behaviors are predictable, but unknown to us, we risk misunderstanding and incorrectly measuring the birds’ behavior if we decide to sample only at certain times. For example, since we have no schools that will be observing the birds during the night, our project will only be able to estimate the difference in the time the male bird incubates relative to the female during daylight hours.

One of the best ways to explain this to young students is to have them think about their own behavior habits. If someone wanted to estimate how much time they spend eating, and they only recorded their observations during the lunch hour, then it would look like they spend most of their day eating. However, if someone picked randoms times to observe the students, it is very unlikely that all of the observations would be during meals.

We are employing a clustered random sampling protocol. It is clustered, in that we have grouped time into five-minute intervals, and each minute within the time intervals is recorded. Here is the sampling protocol:

• Your class has been given a randomly selected time for each day during the second week of the project. (Data collection times are assigned by Dunrovin Ranch within your available times.)
• There are five start times in the Nest Observations Data Form PDF  – one for Monday, Tuesday, Wednesday, Thursday, and Friday. Begin your observations each day at the assigned times and record the data.
• For each one-minute observation, students should start their observations as the minute hand on the clock hits 12 and end their observations exactly 60 seconds later.
• We suggest practicing this protocol during the first week of the project to ensure that your students are ready to begin in earnest in the second week.
• You may want to print out a copy of the Nest Observations Data Form PDF for each student so they can collect their own observations. This should be the fun part for students – carefully observing, deciding which bird is doing what, and recording it on the form.

 

Data Collection Sheet