Firstly, as mentioned in the source, a prime minister may choose to appoint those who have shown and proven that they can deliver in their departments. It says in the source that ‘the prime minister sees the second half of this parliament as the delivery phase’. This shows that a prime minister would want to put those in positions of power who have evidence showing that they are successful in the policies that they implement and can do this effectively. Therefore they would not want to promote, and would want to dismiss, those ministers that have not delivered and whose performance has been dissatisfactory. For example ‘Caroline Spelman’ is likely to be a victim of being sacked or demoted as she ‘has failed to recover from the fiasco of failed plans to sell off parts of the national forest’.
Also suggested in the source is the fact that other influential politicians may have an effect on the prime ministers appointments or dismisses. It says ‘the appointment of Mitchell shows the influence of George Osborne, his close supporter’. Because George Osborne is the Chancellor of the Exchequer he would be an important MP, the fact that he supports another minister would encourage David Cameron to promote this minister. This influential minister may work particularly well, or agree on many policies with another politician. Equally if an important minister does not support another politician, or does not collaborate well with them, they are more likely to be dismissed.
Another factor that the prime minister might consider when reshuffling the government ministers is the political preference of the ministers as a whole. If the a new prime ministers is appointed they will have a similar view to the rest of their party, but because of party divisions and factions within the party, they may be slightly more left wing, right wing, more radical or less radical. According to their views they may want to change the political balance of their ministers to reflect the ideologies they believe in. This promotes consistency with policies implemented. An example of this is when Jeremy Corbyn was elected leader of the labour party in 2015, which was followed by a government reshuffle due to the fact that he was slightly more radical, and left leaning, than the current majority of the party.