The Black Cats have leaked 18 goals in their first eight Premier League matches, leaving them with the worst defensive record in the English top flight
Allardyce believes that ensuring his team are more solid will be the most important improvement he can make in the short-term future.
"I think I just have to improve the defensive record," he told Sunderland's official site. "If I can that priority right first, we will start winning points and we will start winning football matches."
Sunderland have failed to win any of their Premier League matches to date, and their struggles were summed up by their most recent performance.
The Black Cats led 2-0 against West Ham United, but they surrendered their lead in the second half and ultimately were left hanging on for a point.
Sunderland are already five points away from safety, but Allardyce has a history of making teams hard to beat.
The 60-year-old is a manager who specialises in producing teams who are tough to break down, and he will need to ensure that he quickly gets to work with Sunderland's defence, when all his players return from international duty.