Coherence and Cohesion

Coherence means the connection of ideas at the idea level, and cohesion means the connection of ideas at the sentence level. Basically, coherence refers to the “rhetorical” aspects of your writing, which include developing and supporting your argument (e.g. thesis statement development), synthesizing and integrating readings, organizing and clarifying ideas. The cohesion of writing focuses on the “grammatical” aspects of writing. 

Here are some examples that illustrate the importance of connecting your ideas more effectively in writing.

The hotel is famous. It is one of the most well-known hotels in the country. The latest international dancing competition was held at the hotel. The hotel spent a lot of money to advertise the event. Because the hotel wanted to gain international reputation. But not many people attended the event. (The connection of ideas is not very good.) 
    
The hotel, which is one of the most well-known hotels in this region, wanted to promote its image around the world by hosting the latest international dancing competition. Although the event was widely advertised, not many people participated in the competition. (The connection of ideas is better than in the first example.)

The latest international dancing competition was held at the hotel, which is one of the most well-known hotels in this region. The hotel spent a lot of money on advertising the event since it wanted to enhance its international reputation; however, it failed to attract many people. (The connection of ideas is better than in the first example.)

What is Cohesion & Coherence?

Cohesion and coherence aren't too difficult to explain.  Cohesion refers to connectivity in a text.  Coherence refers to how easy it is to understand the writing.

Cohesion & Coherence

"My favourite colour is blue.  I like it because it is calming and it relaxes me.  I often go outside in the summer and lie on the grass and look into the clear sky when I am stressed.  For this reason, I'd have to say my favourite colour is blue."

This sentence is both coherent and cohesive, but let's focus on the cohesion first.  I've highlighted the ways that each sentence is connected to the sentence before.

Cohesion with NO Coherence

Now, here is a sentence that has cohesion but is not coherent.

"My favourite colour is blue.  Blue sports cars go very fast.  Driving in this way is dangerous and can cause many car crashes.  I had a car accident once and broke my leg.  I was very sad because I had to miss a holiday in Europe because of the injury."

Coherence with NO Cohesion

Now, let's take a look at a sentence that is coherent but not cohesive.

"My favourite colour is blue.  I'm calm and relaxed.  In the summer I lie on the grass and look up."