Teaching children in a way that breaks words down into their constituent parts, also known as phonics, helps children from disadvantaged backgrounds and those who don't have English as their first language to learn to read.
This has been proved through research conducted by the London School of Economics (LSE).
Up until the age of seven, this method has been shown to be the most successful, although once children have grasped the basics, it doesn't give any further progression than other teaching methods.
This study is the first large-scale analysis that has looked at the impact of intensive teacher training in phonics on pupils' attainment in teacher assessments and tests at ages five, seven and 11.
The data showed that it had a significant impact at ages five and seven, but that the effects had levelled out by age 11.
However, the benefit of students advancing more at an early age is that they are then able to progress further in other areas of their education. In addition, those who came from poor family backgrounds or who did not speak English as a first language received significant long-term benefits from synthetic phonics, according to the study.
The Department for Education said: "We are determined to raise literacy standards and phonics is key to this, giving children a solid grounding in reading in their early primary school years."