Summary: Both active and passive forms are possible and acceptable in technical writing Consider what the focus of your sentence is i.e. what will you put first in the sentence? Make sure your sentence is clear, concise and precise Use passive when you want to emphasise the object and the actor is already clear and / or unimportant Use active when you want to make it clear who the actor is or when it is more personal e.g.  your opinion / hypothesis / idea.

A commonly asked question from students is whether it is possible to use the active voice in technical writing i.e. ”we did the experiment” instead of the passive voice i.e. ”the experiment was done” (see Engonline for advice on formulating the passive). The answer is yes, it IS possible to use the active voice in technical writing and many successful technical writers do so, but be aware of the stylistic choice you are making. There are different attitudes to this as well within disciplines and amongst supervisors so it is good to check the conventions of your field. See the table below for advantages of the active vs passive (the text in blue is the recommended version).

Advantages of Active	Advantages of Passive
can be more concise and easier to read Passive: ”the health hazards have been compared by the environmental authority” Active ”the environmental authority have compared the health hazards” (fewer words)	focus on the object which can often be more interesting in technical texts Active: ”We structured the interviews to aid in the fulfilment of Objective (2). We chose qualitative interviews. We followed certain interview themes” Passive: ”The interviews were structured to aid in the fulfilment of Objective (2). Qualitative interviews were chosen using certain interview themes” (here the actors are obvious i.e. the researchers in this case, so it’s more helpful to focus on the interviews)
can be more precise Passive: ”the health hazards have been compared”  (unclear actor, we don’t know who did this) Active ”the environmental authority have compared the health hazards”	more formal (see Style and register)  In the above examples, some would argue that the 2nd example is more objective and detached which can be what is expected from scientific writing.
can be clearer Be careful of expressions like ”it is thought” ”it is found” – make it clear who thinks and who finds especially in the discussion section of your paper.	can be less repetitive In the active example above where, as already stated, the actors are clear, the ”we” sounds repetitive and informal.

Tips: Certain sections of the report / thesis work better with active / passive than others. For example, the introduction section can often contain more active forms and the method section more passive forms, but check articles in your own discipline for this. Even if ”we” is possible. However, it is good practice to avoid starting the sentence with ”we” and instead start with an introductory adverb, infinitive phrase, or dependent clause which gives it a less heavy emphasis and links the information to previous information e.g. Additionally, we conducted interviews … Being qualitative interviewers, we followed certain themes Given a choice between quantitative and qualitative interviews, we chose the latter since …

Which is better in the examples below?

1. Passive: ”DNA was extracted from tissue and feather samples”

2. Active: ”We extracted DNA from tissue and feather samples”

3. Active: ”The authors extracted DNA from tissue and feather samples”

4. Active: ”One extracted DNA from tissue and feather samples”

Some discussion of the examples above:

1. This works well if we want to focus on the DNA and we are clear (or maybe it is unimportant) who did the extracting.

2. This works well if we want to make it clear who carried out the action.

3. This is often considered to be a more formal way of writing ”we”. A number of style guides react against it arguing that it is rather pompous and over complicating the issue (see the Eloquent Science blog ) but it can be a useful way to avoid repeating ”we”.

4. Some people argue that ”one” is more formal than ”we” but avoid it unless you want to sound like a member of the English royal family.

Increasing use of active impersonal in technical writing Active impersonal: ”the chapter describes”, ”the discussion argues”, ”the experiment shows” Active personal: ”in chapter 3, we describe”, ”in the discussion, we argue” Passive: ”the system is described in chapter 3” Example 1 has the advantage of being both concise and clear though some react to the fact that an inanimate object is doing the action i.e. clearly a chapter cannot describe something, and it is the writer who is describing something in the chapter. All three examples are wording choices commonly found in technical writing.

For more information / further reading on this area:

1. Hyland, K. (2001). Humble servants of the discipline? Self-mention in research articles. English for specific purposes, 20(3), 207-226.
2.  Harwood, N. (2005). ’I hoped to counteract the memory problem, but I made no impact whatsoever’: discussing methods in computing science using I. English for Specific Purposes 24: 243-267.
3. Purdue Online Writing Lab.
4. Rienecker, L., Jørgensen, P. S., & Skov, S. (2013). The good paper: a handbook for writing papers in higher education. International Specialized Book Service Incorporated.
5. Alley, M. (1996). The craft of scientific writing. Springer.