Every good student knows that each paper without distinction of its type should begin with an introductory part. It goes without saying that any academic work, and not even an academic one, should have an opening statement which will present the main idea of the work. However, besides the introduction, some academic works such as, for example, a research paper or a dissertation should also include an abstract. And for some reason, there are quite many cases when students confuse an abstract of a research paper with an introduction. As a result, instead of an introduction, they write things which should go in an abstract and vice versa. Certainly, that is a serious error which will cost many points to a student even though the entire academic work may be written brilliantly and contain all the necessary research, analysis, statistic data, and so on. To put a period on this issue, let’s find the answer to the question “What is the difference between an abstract and an introduction?” and eliminate any chance for misunderstanding of these two quite the opposite parts of a paper.
Abstract Versus Introduction. What Is the Difference?
To get the differences between these two terms, let's’ first take a look at each of them separately. Probably, the brief explanation which you have seen before elsewhere leads to the confusion of these terms. So, what is an abstract in a research paper and what it has to include?
The goal of an abstract is to inform the reader about the topic of the papers, goals, methods of research, and the findings. In other words, it introduces a very short overview of the research that you have conducted. The goal of an introduction is to inform the readers about the topic of the paper, the purpose of your research, and what you are going to find. As you can see, there are indeed some things in common like the goal of a paper and introducing the topic, and that is probably the reason for confusion.
To make it is easier to get the difference, pay attention to the introduction name which states that you are going to introduce something. Not to explain or conclude things as well as not to focus on something specific. An introduction is like a book cover where you see a title and only make suggestions what the book is about. An introduction will never give the readers information about the results of the research since the research is not conducted yet. It is the initial part of a paper, and a person who writes it only sets the goals and has the direction, but cannot make any conclusions yet.
An abstract is written after you have completed the paper and gotten the answers to the questions that were set in the beginning. Your work is over, and now you have everything to make an abstract for your paper. In an abstract, you indicate the goals which you set, the methods you used to get the required results, and whether your research has satisfied the initial objectives of your work.
Another thing which might help to understand the difference is the length of these pieces of work. For an introduction, there are no strict requirements since it depends on the size of the entire paper. For example, even a 1-page essay has an introduction, but in case of 250-300 words work, the introduction could hardly be over 50-70 words, otherwise, you will not have enough words for the body and the conclusion. If we are talking about a research paper of 10 pages, then an introduction can be and even should be about 1-page long. For a dissertation which may consist of over 100 pages, the length of the introductory part may be 3-5 pages depending on the topic. So, the length of the introduction should be in proportion to the length of the whole work, and it usually takes up to 8-10% of a paper.
But what about an abstract? How long should an abstract be? Here the answer is more accurate. The length of an abstract is usually about 1 page or can be a bit more if necessary, but you will hardly find less since you should address the topic, goals, methods, and findings there. So, one page is just enough to answer all these questions. 
Abstract vs. Introduction. The Bottom Line
Now, let's draw a bottom line and once again briefly repeat what an abstract and an introduction should have. Use this guide as a reminder if you forget what the difference is.
An abstract should include:
- Topic
- Goals
- Methods
- Results
An introduction should include:
- Topic
- Goals
- The importance of the study