The Research Design criterion assesses the extent to which the student effectively communicates the methodology (purpose and practice) used to address the research question.
3 strands, maximum 6 points
The research question needs to be described within a specific and appropriate context.
Methodological considerations associated with collecting relevant and sufficient data to answer the research question are explained.
The description of the methodology for collecting or selecting data allows for the investigation to be reproduced.
research question needs to be unique to each student
independent variable is present
dependent variable or derived dependent variable is present
variables are quantifiable
background context or theory is relevant and focused
context of the independent and dependent variables is relevant and focused
choice of data sources, in the case of databases, is explained and their reliability is commented on.
Research question
A research question could look like this: how does (dependent variable) depend on (independent variable)? However, the research question may not necessarily include the actual dependent variable but a derived value. For example, for the question “What is the effect of X on the rate of change of Y?”, the rate of change would be derived from measured values. The link between the dependent variable and the investigation—the context—would need to be established in the background. This may not be the case for simulations that may result in derived values such as rates. In these cases, the rate would be the raw data.
Context (Background)
An appropriate context needs to be described when formulating the research question. The context should help with understanding the specific details of the research question and with the implementation of the investigation.
This context includes the scope and limitations of the known theory or phenomenon. The investigation’s background needs to be focused and specific.
Hypothesis and quantitative prediction
A hypothesis and quantitative prediction can help to set the research question in context. A hypothesis usually allows students to explain the relationships between the variables mathematically, and to provide an indication of the nature of the relationship. Typically, there will be some known theory that is used to form a hypothesis. Then it will be possible to form a prediction based on the hypothesis. If this is included, it must be addressed in the conclusion.
Preliminary or trial investigation is described and assessed
Description of measuring the dependent variable
Range and intervals of the independent variable
Sampling rate
Method of controlling or monitoring each variable
Discussion of other factors that would need to be controlled
Techniques used to ensure adequate control (fair testing)
Quantity of data collected, including sufficient repetitions given the nature of the system investigated
Qualitative observations.
The protocol for collecting relevant data is present
Variables
Independent variable
Explain your choice of method for measuring the independent variable. The rationale for the range and intervals used for the independent variable needs to be explained in the context of the investigation.
Dependent variable
The dependent variable needs to be accurately defined and explained. If the investigation is looking for a trend, a minimum of seven data points is expected for the independent variable. In some exceptional cases, less may be accepted. Explain the range chosen and your choice of method of measuring the dependent variable.
In many experiments the sampling rate needs to be considered to ensure that meaningful but not excessive data are collected. This can often be best determined during trialling (preliminary experiments). Repeats are a standard expectation, to ensure the validity of the results.
Control variables
You should identify which variables can be controlled and how this is achieved in your method. It should also identify which variables cannot be controlled but need to be monitored (eg room temperature).
Preliminary experiments
You should include a record of preliminary experiments, which you will use to refine your method and make decisions on how to collect sufficient data to answer the research question in a 10-hour period of investigative work (this includes the designing and trialling). The quantity of data collected needs to be realistic.
Equipment
Details of equipment, and measuring instruments and their sizes, must be included to assess their suitability and the stated uncertainties.
logical sequence
the presence of essential information
avoid unnecessary repetition
the sketches, diagrams, charts and photographs used to illustrate the investigation
include the use of screenshots to explain how the data were captured (in the case of investigations using databases and simulations)
correct use of scientific terms
the selection of measuring instruments and their sizes
brand names of items used as variables.
Illustrate your investigation using annotated sketches/diagrams/photographs of the experimental set-up. These can help to describe the investigation, with minimal impact on the word count. Illustrations should only be included when they add value. For example, diagrams of balls, rulers and stopwatches out of context are superfluous.
Method
The reader needs to understand how the methodology and procedures were implemented, and how the equipment and other materials were used. There needs to be enough information so that the reader could, in principle, repeat the investigation. The procedure should be clear and detailed enough to be reproduced. You can use a numbered step-by-step method but avoid unnecessary repetitions.
Risk assessment
Expectations:
judicious consumption of materials
appropriate disposal of waste
consideration of impact and safety on field sites
consideration of safety and environmental concerns.
Risk assessment is an important part of experimental design. However, issues concerning safety, ethics and environmental impact may not apply to the same degree for each investigation. The impact of risk assessment on the mark awarded for the criterion will depend on whether there are significant safety, ethical and environmental factors that are, or need to be, considered by the student. It should be clear that these risks have been mitigated. Stating an issue indicates the student is aware of it, but not necessarily that the issue has been addressed.
If an investigation has no safety, ethics or environmental considerations, the student should include a statement to this effect.
For work with databases, simulations or modelling systems, safety and environmental concerns will not be relevant. However, ethical issues can arise for the use of databases, and it is to the student’s credit if they are raised.
Source: Roberta Rodriguez, IB Physics Teacher