Cohesion within and between sentences

(While vs. However)

‘While’ and ‘However’ are both cohesive devices. They connect ideas, but not in the same way. 

‘While’ connects ideas within a sentence. 

‘However’ comes between ideas and connects them. 

Examples:

The unemployment rate has been decreasing steadily. However, inflation has been on the rise. (Between two ideas or sentences)

While some people advocate for controlling government spending, others argue for policies to boost economic activity. (Inside a sentence)

Words such as ‘while’ and ‘whereas’ cannot start an independent sentence.

*Incorrect: 

The economy has worsened in recent months. *While, exports of technology products have increased. 

Correct: 

The economy has worsened in recent months. However, exports of technology products have increased. 

When the ‘while’ clause shows contrast, then it is set off by a comma. This is also true for ‘whereas.’ 

While the figures increased in the UK, they showed mixed success in Portugal. (Note the comma)

Figures showed mixed success in Portugal, while they increased in the UK. (Note the comma)

I hope this has been helpful.