Module 2.1: Writing topic sentences

This module offers ideas on simple paragraph construction. It is most suitable for essays to ask the writer to explain why/how some phenomena occur. For more complex paragraph writing, see module 2.2. The number of sentences in a paragraph is unimportant as long as the paragraph develops the main idea clearly. A paragraph has at least two and sometimes three stages:

(a) The topic sentence (essential)

The topic sentence announces to the reader what the paragraph is about. It is often the first sentence of the paragraph.

(b) A sufficient number of supporting sentences (essential)

These sentences develop the idea of the topic sentence and usually refer to expert opinion.

(c) A concluding sentence (optional)

Sometimes a paragraph may conclude a sentence that 'rounds off' your argument before moving on to the next point in your essay. But for a very short essay this is often not necessary.


Example 1: Topic sentence

Good oral hygiene practices should be commenced in early childhood (Topic Sentence). Early oral hygiene practice maximises a child’s chance of better overall health throughout life. Regular tooth brushing, even in early childhood, is an important practice to minimise the development of caries. Maintaining good dietary habits such as eating low sugar foods and drinking non sugary drinks is also essential for oral health. While parents and carers are best placed to ensure good oral practices, dental professionals can assist by advising about oral health care for each child (NSW Ministry of Health, 2014).

Source: NSW Ministry of Health (2014) Early childhood oral health guidelines for child health professionals, (3rd ed). North Sydney, NSW Australia. Available:

Topic sentence

A topic sentence does more than tell the reader what the topic is. It also limits what aspect of the topic will be discussed: This is called the controlling idea. In the text below, the controlling idea is adolescents (who participate in sport). Notice the terms that refer to adolescents: ’puberty’, ‘adolescents’ and ‘adolescence’.

Example 2: Topic sentence
Analysis: Move the mouse over to the highlighted sentence below to see analysis.

Pain is the most common presenting complaint in Osgood-Schlatter disease.

Osgood-Schlatter Disease (OSD) occurs mainly in adolescents who participate in sport. The pain is exacerbated by running, jumping, kneeling and squatting. Normally, OSD occurs during growth spurts in puberty. For girls with ODS they commonly complain of pain at around 11-12 years of age and for boys the onset of OSD typically occurs between 13-14 years of age. Generally, adolescents are encouraged to continue with their sport activity unless pain becomes severe. When the rapid skeletal growth of adolescence is completed, the pain associated with OSD usually disappears (Sullivan & Young, 2014).

Source: Sullivan, JA., & Young, CC. (2014). Osgood Schlatter Disease. Medscape. Retrieved 17/3/15 from

Controlling idea

There is an urgent need for both health practitioners and local communities to work together to meet the challenges of climate change (Blanshi, Mc Michael., & Karoly, 2007).

The challenges of climate change is the topic while “health practitioners and local communities … work[ing] together” is the controlling idea.

Example 3: Controlling idea
Analysis: Move the mouse over to the highlighted sentence below to see analysis.

Climate change and primary health care

1There is an urgent need for both health practitioners and local communities to work together to meet the challenges of climate change (Blanshi, Mc Michael., & Karoly, 2007). 2Broadly the authors argue that there will be mental and physical health impacts as the climate changes. 3It is expected the harsh, dry parts of Australia will experience worsening drought conditions which are likely to impact on the mental health of communities.4Whereas in wetter areas, it is expected that mosquito borne diseases will increase with associated increases in physical illness. 5The authors warn that Australia wide each community will need to assess who will be most vulnerable within their community and how these vulnerabilities can be addressed. 6An implicit concern seems to be the anticipated financial and social under-resourcing by government to meet these increasing demands.

[ Source: Blanshi, G., Mc Michael, X., & Karoly, D. (2007). Climate change and primary health care. Australian Family Physician, 36(12), 986-989.]


2.1.2 Sufficient number of supporting sentences

The supporting sentences develop the Topic Sentence by using one or more of the following features

  • discussing
  • explaining
  • giving reasons
  • providing examples
  • quoting etc.
  • referring to experts

To achieve the purpose of the supporting sentences the writer typically needs 5-10 sentences to do so. If you find you are commonly writing paragraphs of 2-3 sentences then you need to rethink your structure.

Example 3: Sufficient number of supporting sentences
Analysis: Move the mouse over to the highlighted words/sentences below to see analysis.

It is difficult to speculate why patients in this study did not mention family care (family support). Maybe they did not see this as the nurse's role. On the other hand, it appears that both patients and families find the environment of the palliative care unit in this nursing home comfortable. It provides a safe, free homely environment that these patients want. Therefore the patients may assume family care is being given.

[Source: Unknown]

The above example only utilises one type of supporting evidence, which is giving reasons or interpretation. This is inadequate. A more satisfactory example would be:

Example 4: Supporting sentences (highlighting controlling idea)
Refer to explanations of the writing of this text at the end of this paragraph

Stress, also referred to as psychological distress, can be caused by a variety of physiological, psychological and emotional factors. When a person is suffering extreme stress, raised cortisol levels in the brain can physiologically damage both the structure and the functioning of the brain. Other physiological effects can include cardiovascular and gastrointestinal changes in the body (Frodi & O’Keane 2013). Psychological harm can also occur when a stressed individual resorts to harmful behaviours such as excessive use of alcohol or recreational drugs in an attempt to cope with their stress. Anxiety or mood disorders may also be indicators of excessive stress and may damage mental health (Hogan, 2013). One indicator of emotional stress is burnout, or emotional exhaustion, which leads to decreased performance in the activities of daily living.

In western countries, up to 45% of nurses suffer burnout which is related in part to high workloads (Kowalski, Ommen, Driller et al., 2010). In addition, Emotional stress has a negative impact on both physiological and psychological wellbeing. While we need some stress to achieve optimal performance in our lives, too much stress is counterproductive for successful participation in daily life (Hogan, 2013). Thus the individual needs to monitor their stress levels to achieve a balance of physical, psychological and emotional wellness (Hogan, 2013) and, if necessary to seek professional advice.

Explanations of writing

  1. Stress is the topic.
  2. Physiological, psychological and emotional factors are the controlling ideas.
  3. This paragraph also offers the reader further explanations of different types of stress to support the topic sentence as well as further explanation of different factors related to the controlled ideas
  4. This paragraph offers the reader a variety of sources and citations.

Frodi, T., & O’Keane, V. (2013). How does the brain deal with stress? A review with focus on developmental stress. HPA axis function and hippocampal structure in humans. Neurobiology of Disease, 52, (April), 24-37. doi: 10.1016/j.nbd.2012.03.012.

Hogan, C. (2013). Chronic Stress: An approach to management in general practice. Australian Family Physician, 42,(8, August), 542-545.

Kowalski, C., Ommen, O., Driller, E., Ernstmann, M., Kohler, T., & Pfaff, H. (2010). Burnout in nurses- the relationship between social capital in hospitals and emotional exhaustion. Journal of Clinical Nursing, 19,1654-1663. doi: 10.1111/j.1365-2702.2009.02989.x

Example 5: Supporting Sentences

Awareness of the increase in superbugs as a result of the overuse of antibiotics has been recognised for several decades. Researchers are currently using metals such as copper and silver to fight antibiotic resistance (Masterton, 2015). One highly specialised response is the use of nanoparticles of silver to fight bacteria (Heger, 2008). Bacteria such as Staphylococcus aureus (MRSA), have developed resistance to the antibiotics that were once commonly used to treat them (Victorian Govt. Health Information, 2009; Mayo Clinic, 2010). Nanoparticles of silver destroy the physical structure of the bacterial cells, unlike antibiotics which may only suppress the activity of the bacteria (Lucia as cited in Heger, 2008). Within the research community there is hope that the spread of superbugs can be limited by the innovative use of nanotechnology.

[Based on an article Masterton, A. (2015, April, 26). Invasion of the superbugs. The Sun Herald, pp. 24-25. ]

Example 6: Concluding sentence

The following paragraph has a concluding, summing up sentence (in bold) because the authors are about to begin a new point.

The NSW Rural Health Plan: Towards 2021 (NSW RHP) (2014) aims to improve the provision of health care in rural NSW by boosting initiatives for patient care and expanding training for health care professionals. Patient care initiatives include providing patients with health care ‘as close to home as possible and in a way that is coordinated and seamless’ (p. 1). The NSW RHP also develops new strategies to help patients gain access to the latest medical technology close to their residence as this had been promised by successive governments over many decades.  With the advancements in technological services local provision of health care is possible and benefits not only patients but health care professionals as well. For example, the latest telecommunication technologies, such as telemedicine, provides health professionals with access to specialist services for clinical care. However, new technological services require collaboration and changes in workplace practices (p.30) and a new plan for ongoing professional development is also included in the NSW RHP (2014). The NSW RHP also emphasises the importance and value of creating linkages with a range of health service providers and ancillary services to maximise health care outcomes for rural and regional Australians. This integrated approach will provide both patients and health professionals with a superior experience of health delivery.

NSW Ministry of Health (2014). NSW Rural Health Plan: Towards 2021.  Retrieved April 22, 2015 from  


Before you proceed to the next module, please complete these quizzes. Make sure you answer all the questions before you check the answers.

Part 1

Part 2