What a control is for

1. A control is a step you build into the way you run a study so that an extraneous variable cannot move your results.
2. The target is a fair comparison in which the conditions differ in the independent variable and in nothing else.

Standardised procedures

1. A standardised procedure is a fixed set of steps, instructions, materials and timings used with every single participant.
2. You write the instructions out word for word, run every session in the same kind of room and give everyone the same amount of time.
3. The problem it solves is situational variables drifting from one participant to the next, so the setting cannot be the reason one group scored higher.

Counterbalancing

1. Counterbalancing means splitting your participants in half and having each half do the two conditions in the opposite order.
2. The problem it solves is order effects, which appear when everyone takes part in both conditions and doing one first changes how they do the second.
   1. People may get better through practice or worse through boredom and tiredness, and either way the order rather than the independent variable would be shifting the scores.
3. Counterbalancing does not remove those effects, it spreads them evenly across both conditions so that they cancel out.

Randomisation

1. Randomisation means letting chance, rather than your own judgement, decide something about how the study is run.
2. You can randomise the order of the items in a task, the order the materials are presented in, or which condition each participant takes part in.
3. The problem it solves is your own preferences quietly shaping the study, such as putting the keenest students into the condition you hope will win.
4. When chance decides who goes into each condition, participant variables such as ability and motivation are more likely to spread evenly than to pile up in one group.

Single-blind techniques

1. In a single-blind technique the participants are not told which condition they are in or what the study expects to find.
2. The problem it solves is participants working out the aim and then behaving in the way they think is wanted, which is known as demand characteristics.
3. With nothing to guess from, they have no way of helping the prediction along and behave more naturally.

Double-blind techniques

1. In a double-blind technique neither the participants nor the person running the session knows which condition is which.
2. The problem it solves is the researcher giving away what they expect, through tone of voice, extra encouragement or the way they mark an answer that could go either way.
3. It therefore holds down the expectations of the participants and of the researcher at the same time, which makes it the stronger of the two techniques.

Turning this into marks

1. Name the control and say what it stops in that particular study.
2. Write the control in the words of the scenario, such as reading the same instructions to both Year 9 classes.
3. The mark most often lost comes from defining a control in general terms without applying it to the study in front of you.