Avoiding plagiarism, self-plagiarism, and other questionable writing practices: A guide to ethical writing

Miguel Roig, Ph.D.

Examples of paraphrasing: Good and Bad

The ethical writer takes great care to insure that any paraphrased text is sufficiently modified so as to be judged as new writing. Let’s consider various paraphrased versions of the following material on the electrochemical properties of neurons (taken from Martini & Bartholomew, 1997). In acknowledging the source, we will use the footnote method commonly used in the biomedical sciences. The actual reference would appear in the reference section of the paper.

“Because the intracellular concentration of potassium ions is relatively high, potassium ions tend to diffuse out of the cell. This movement is driven by the concentration gradient for potassium ions. Similarly, the concentration gradient for sodium ions tends to promote their movement into the cell. However, the cell membrane is significantly more permeable to potassium ions than to sodium ions. As a result, potassium ions diffuse out of the cell faster than sodium ions enter the cytoplasm. The cell therefore experiences a net loss of positive charges, and as a result the interior of the cell membrane contains an excess of negative charges, primarily from negatively charged proteins.”¹ (p. 204).

Here is an Appropriate Paraphrase of the above material:

A textbook of anatomy and physiology¹ reports that the concentration of potassium ions inside of the cell is relatively high and, consequently, some potassium tends to escape out of the cell. Just the opposite occurs with sodium ions. Their concentration outside of the cell causes sodium ions to cross the membrane into the cell, but they do so at a slower rate. According to these authors, this is because the permeability of the cell membrane is such that it favors the movement of potassium relative to sodium ions. Because the rate of crossing for potassium ions that exit the cell is higher than that for sodium ions that enter the cell, the inside portion of the cell is left with an overload of negatively charged particles, namely, proteins that contain a negative charge.

Notice that, in addition to thoroughly changing much of the language and some of the structure of the original paragraph, the paraphrase also indicates, as per guideline 5, that the ideas contained in the rewritten version were taken from another source. When we paraphrase and/or summarize others’ work we must also give them due credit, a rule not always applied by inexperienced writers.

Let’s suppose that instead of paraphrasing, we decide to summarize the above paragraph from Martini and Bartholomew. Here is one summarized version of that paragraph:

The interior of a cell maintains a negative charge because more potassium ions exit the cell relative to sodium ions that enter it, leaving an over abundance of negatively charged protein inside of the cell.¹

In their attempts at paraphrasing, sometimes authors commit ‘near plagiarism’ (or plagiarism, depending on who is doing the judging) because they fail to sufficiently modify the original text and thus, produce an inappropriately paraphrased version. Depending on the extent of modifications to the original, the extent of text involved, and on who is doing the judging, inappropriate paraphrasing may constitute an instance of plagiarism. For example, the following versions of the Martini and Bartholomew paragraph are inappropriately paraphrased and are, thus, classified as plagiarized versions:

Inappropriate paraphrase (version 1):

Because the intracellular concentration of potassium ions is _ high, potassium ions tend to diffuse out of the cell. This movement is triggered by the concentration gradient for potassium ions. Similarly, the concentration gradient for sodium ions tends to promote their movement into the cell. However, the cell membrane is much more permeable to potassium ions than to it is to sodium ions. As a result, potassium ions diffuse out of the cell more rapidly than sodium ions enter the cytoplasm. The cell therefore experiences a _ loss of positive charges, and as a result the interior of the cell membrane contains a surplus of negative charges, primarily from negatively charged proteins.¹ (p. 204).

A comparison between the original version of the Martini and Bartholomew paragraph to the ‘rewritten’ version above reveals that the rewritten version is a mere copy of the original. The few modifications that were made are superficial, consisting merely of a couple of word deletions, substitutions, and additions. Even though by the insertion of a reference note (¹) the writer has credited Martini and Bartholomew with the ideas expressed, most of the words and structure of the original paragraph are preserved in the rewritten version. Therefore, the reader would have been misled as to the origin of the writing.

Inappropriate paraphrase (version 2):

The concentration gradient for sodium (Na) ions tends to promote their movement into the cell. Similarly, the high intracellular concentration of potassium (K) ions is relatively high resulting in K’s tendency to diffuse out of the cell. Because the cell membrane is significantly more permeable to K than to Na, K diffuses out of the cell faster than Na enter the cytoplasm. The cell therefore experiences a net loss of positive charges and, as a result the interior of the cell membrane now has an excess of negative charges, primarily from negatively charged proteins.¹ (p. 204).

At first glance this second ‘rewritten’ version may look as if it has been significantly modified from the original, but, in reality, is not unlike the first inappropriately paraphrased version in that only superficial changes have been made to the original. In this particular case, the writer has made a seemingly disingenuous change, by substituting the names of the atoms by using their chemical symbols (e.g., sodium = Na). In addition, the order of the first two sentences was changed giving the appearance of a substantial modification. However, as in the previous version, the language and much of the rest of structure is still too similar to the original.

Again, we must emphasize that when we paraphrase we must make every effort to restate the ideas in our words. Here is another properly paraphrased version:

Appropriate paraphrase (version 2):

The relatively high concentration gradient of sodium ions outside of the cell causes them to enter into the cell’s cytoplasm. In a similar fashion, the interior concentration gradient of potassium ions is also high and, therefore, potassium ions tend to scatter out of the cell through the cell’s membrane. But, a notable feature of this process is that Potassium ions tend to leave the cell faster than sodium ions enter the cytoplasm. This is because of the nature of the cell membrane’s permeability, which allows potassium ions to cross much more freely than sodium ions. The end result is that the interior of the cell membrane’s loss of positive charges results in a greater proportion of negative charges and these made up mostly of proteins that have acquired a negative charge.¹