An important aspect of an introduction paragraph is having either a thesis (aka contention) or a hypothesis. Both have their own unique role, and the type of writing will decide which is a best fit.
Thesis or Contention
Purpose: One of the defining attributes of a thesis statement is that it is a claim or interpretation of available evidence. A thesis statement is supported using a range of quantitative, qualitative and mixed method research, and seeks to provide a perspective on the data and information found/explored.
A quality work environment when studying is the most valuable way for students to increase their overall results.
Note: In the above example, social scientists could argue whether or not work environment is the MOST valuable way to increase results or if there are other factors that are equally significant.
Purpose: One of the defining attributes of a hypothesis is that it may be either proven or disproven. A hypothesis is supported within a text using quantitative data and replicable experiments, and seeks to provide an objective truth based on research and information.
If a student increases the amount of light when studying, then their performance on tests will decrease.
Note: In the above example, social scientists could either prove or disprove this hypothesis using studies into student performance across a large sample size.