Using semi-colons instead of commas

In certain circumstances, the semi-colon can perform the same functions as the comma.

Semi-colons can be used instead of commas to separate items in a list when those items already contain commas; for example:

The development of poverty in the third world can be linked to several factors, some of which include: the change to the production of cash crops after the upheavals of slavery and the need for a substitute income; the cultural heterogeneity and consequent political instability of newly formed nation states, resulting from the arbitrary imposition of borders by colonial powers; and, more recently, unscrupulous lending by developed nations, leading to crushing debt burdens.
Of those recommendations suggested by the Space Team, a Quality Improvement Team, the following were progressively implemented in 1997: a large compactus was installed on the top floor to house less frequently used items; the office, and its associated equipment, was relocated from the first floor to the ground floor ; and indexes and less frequently used items were transferred to the compactus.

Semi-colons should also be used instead of commas before connective words like therefore, however, for instance, for example, in contrast and in addition. Some examples are provided below:

This compares favourably with other organisations ; for example, Queensland University of Technology reported 73% usage in 1996 and the University of Sydney Library reported 80% usage in 1995.
Long term memory has a vast storage capacity ; however, the storage capacity of working memory is more limited.
In connectionist or network models of processing, processing occurs along many dimensions simultaneously ; in contrast, the use of a computer metaphor dictates serial processing.

This use of connective words such as however is not to be confused with their other use in sentences such as:

During the 1970s, however, evidence from the field of problem solving emerged indicating short term memory was involved in information processing not just information storage.
From this perspective, therefore, the gender relations and gender hierarchy that existed before the Second World War in Australia are viewed as natural as opposed to unnatural.

In these sentences, the connective word is bounded only by commas because it is interrupting the flow of the sentence, not introducing a new independent clause as in the previous examples.