Friday is the last chance for Washington to produce economic data that might influence the presidential election.

And if recent history is any guide, this — and not the ballot box — is where Republicans should be looking for an election rig.

The Labor Department will announce its employment report for October on Friday morning. The experts see decent job growth of 175,000 last month, which would be higher than the 156,000 new jobs reported in September.

The unemployment rate is expected to drop to 4.9 percent from 5 percent. Any big decline in this figure will immediately cause suspicion — so that won’t happen.

If any trickery occurs, it will likely be in the seasonal adjustments, which can always be corrected at a later date and in the birth/death model that the Labor Department uses to guess at the number of jobs created by “newly born” companies that it can’t prove really exist.

Any change in the seasonal adjustments is difficult to immediately pick out and certainly won’t affect newspaper headlines — it’s just too complicated for most journalists. So this is perfect for rigging the number.

The birth/death guess is equally good for making the jobs report look better than it really is.

In October 2015, the Labor Department added a hefty 178,000 jobs to its count because the model told it that a lot of new businesses were being formed and that was the number of new positions that might have been created by these newbie firms.

This October’s guesstimate should be in that range. Anything significantly higher should be looked at with suspicion.

Like the seasonal adjustment, the birth/death model is corrected later — after the votes are tallied.

For instance, the Census Bureau, which works hand-in-hand with the Labor Department, said the rate of businesses that are starting up in 2014, the latest figure available, was the second-lowest on record.

There are other things going on with the economic data that suggest excessive optimism, if not outright manipulation.

Here’s one: For years, it has been believed by experts that 150,000 additional jobs were needed each month just to absorb people trying to enter the workplace for the first time. So, in order for people who lost their jobs to also get back to work, the monthly growth would have to be more than 150,000.

Just recently, the Federal Reserve lowered that estimate to just 50,000 jobs. It’s like when the Mets didn’t feel they were getting enough home runs to right field. The team moved in the fences and suddenly the stats looked better.

There’s also the recent gross domestic product report from the Commerce Department, which showed annualized growth of 2.9 percent in the third quarter of 2016. What’s strange about that is that the figure was much higher than the 2.1 percent anticipated by the Atlanta Federal Reserve, which tracks GDP on a daily basis.

The GDP figure will also be revised several times after the election. Wanna guess which way those revisions will go?

As I’ve been saying for years, elections are won or lost by the incumbent party in the White House based on how the real economy is doing. And by that I mean how people’s guts — an accumulation of personal experiences and those of their friends — tell them it’s doing.

A couple weeks ago, I caught the Commerce Department fooling with its income data for the nation. It changed the way retirement accounts were counted as “income.”

All tricks.

But the way it stands now, in addition to all her other problems, Hillary Clinton has the pocketbook issues going against her. And no amount of finagling with the data is going to change that.