How do Geographers go about testing the accuracy of a theory such as the Bradshaw Model. 

When testing the accuracy of a model or theory geographers carry out research.  Research is the systematic collection of data which is then used to evaluate how accurate the model idea is when compared with the real world – in this case the real world being the characteristics of the River Lyn.  There are three ways (known as the research methodology) that geographers can collect the data they need to test a model:

  • Quantitative methodology – this involves the collection of data which is numerical and which is sometimes referred to as ‘hard’ data because it is measurable and can often be tested statistically e.g. the speed of a river measured in meters per second at ten points along its course.
  • Qualitative methodology – this involves the collection of information from non-numerical sources such as interviews with people, pictures (e.g. photographs and film) and objects (such as artefacts) which generally do not generate numerical data which can be tested statistically;
  • Mixed methodology – an approach to research which combines collecting information both quantitatively and qualitatively.


Once geographers have decided upon their research methodology the next thing they have to do is to choose the best methods of obtaining the information required.  Data collection methods either involve collecting the required information from primary sources or secondary sources.  Primary data is information which is collected by geographers themselves and is personal to them.  It is original first hand data which only the researcher could have collected.  For example, surveying 100 people in Lynmouth about their views regarding flooding risk is primary data collection.  Secondary data on the other hand is information which has already been collected by someone else other than the researcher but which the researcher uses because it is relevant to their investigation.  A good example of secondary data are the measurements taken along the course of the River Lyn by the Exmoor National Park Team  which appear later in the enquiry to help you in your investigations

Consolidate your thinking

This research investigation will involve gathering data about the characteristics of the River Lyn to compare with the Bradshaw model from a range of sources including:

  • Ordnance Survey maps to identify gradient change and cross section shape of the river;
  • Taking measurements of features of the river such as depth; wetted perimeter, velocity, occupied channel width and mean depth, at different locations along the course of the river;
  • A data base of measurements already collected by the Exmoor National Park Team and referred to above.
  • Satellite images, aerial and land based photographs and video footage of the river at different locations;
  • Accounts of the river written by academic and professional geographers.

What kind of research methodology is being used here and which of the methods being used is collecting information from primary sources and which from secondary sources?


Go to Question 3 - What first impressions of the course of the River Lyn can be drawn from the archive of photographs held by the Somerset Rivers website?