Call it income splitting-lite. The version of the family tax credit announced by Prime Minister Stephen Harper last October was a tweaked version of a family income-splitting announcement he'd first made in the throes of the 2011 election campaign.

The tweaks were aimed at addressing earlier criticism that the measure would only serve to worsen the growing gap between the country's rich and poor, with the biggest tax benefits reserved for the richest families.

But even after the tweaks, some critics (and the parliamentary budget officer) say it's a goodie that will benefit only 15 per cent of Canadian families. And independent analysts have said the biggest tax savings will still go to families with incomes of more than $233,000 a year.

Changes to the universal child care benefit

Benefit rises from $100 to $160 a month for each child under age 6, effective Jan. 1, 2015.

New benefit of $60 a month for each child between ages 6 and 17, effective Jan. 1, 2015.

Above benefits will not be reflected until the July 2015 payments, resulting in a retroactive adjustment.

The enhanced UCCB will replace the current child tax credit as of 2015. But the UCCB changes will not replace the Canada child tax benefit ( CCTB ) you may currently receive.

The government counters that the other parts of its family tax-relief package — enhancements to the universal child care benefit (UCCB) and increases in the child care expense deduction — will benefit all families with children under the age of 18.

But the changes in those two measures will only take effect this year, with the first lump sum payments arriving in July 2015, just a few months ahead of an expected fall election.

Only the income-splitting part of the family package is in effect for the 2014 tax year. So, it's something Canadian families need to familiarize themselves with now as they prepare to file their returns.

Here are the broad strokes of the family tax cut:

It applies only to two-parent families with at least one child under the age of 18 — so, no single parents, no families where both parents are in the same tax bracket, and no childless couples need apply.

It allows the higher-income spouse or common-law partner to effectively transfer up to $50,000 of taxable income to their lower-income partner.

The amount of tax that could be saved by this transfer becomes a non-refundable tax credit that can be claimed by either spouse.

The credit is capped at $2,000.

Federal tax brackets - 2014 tax year:

Up to $43,953 — 15%

$43,954-$87,907 — Tax Rate 22%

$87,908-$136,270 —Tax Rate 26%

$136,270 — 29%

​​Source: CRA

Some of the popular annual tax preparation books that are on the shelves now don't mention the family tax cut as it wasn't announced until late October. But all of the CRA-certified tax software programs take this income-splitting measure into account. So, for those who've been reluctant to use tax software, this may be the year to bite the bullet and start familiarizing yourself with the programs.

Single parents, couples who both have roughly the same income and couples without children will not benefit from the new family tax credit. But they will benefit from other family-friendly tax measures that take effect in 2015. (Sean Kilpatrick/Canadian Press) That's because critics say the new family tax credit isn't the easiest thing to figure out. "Gaining access to income splitting will also require the correct calculation of up to 85 new steps in the 2014 tax forms," says a report from the Canadian Centre for Policy Alternatives, an Ottawa-based think tank. "Given the complexity of the benefit — not only of the calculations but even of its basic understanding — it will almost certainly be misunderstood by tax filers."

Here are some other wrinkles that might not be immediately apparent:

The family tax credit results from what's called a "notional" transfer of income, not an actual split (as with pension income splitting). Income isn't actually transferred from one spouse's return to the other's. Since each individual's actual net income and taxable income doesn't change, there will be no provincial tax savings. This is a federal tax benefit only. Another implication of this "notional" transfer is that benefits that are based on a tax filer's net income, like the GST /HST credit, the Canada child tax benefit and the age amount will not be affected.

GST It doesn't matter how many children under age 18 the family has. Having one child or 10 makes a big difference to a family's financial picture, but it makes no difference for the purposes of this credit.

To be an "eligible" family, there must be at least one child under the age of 18 at the end of the year, and that child must reside with the couple throughout the year. But there are exceptions. If a child is born, adopted or dies during the year, the credit can still be claimed. If one of the spouses or common-law partners dies, the credit will still be available.

Even though the implementing legislation for the family tax credit hasn't been passed yet, the CRA takes the position that the measure is already the law of the land. However, in the event you file for a reassessment because you forgot to claim the family tax credit when you did your 2014 taxes, the CRA will not send any refund until after the measure is passed.

Both spouses must file 2014 tax returns and be Canadian residents to claim the credit.

Both spouses must also not split any pension income they may have.

If either spouse has declared bankruptcy, neither can claim the family tax credit in the year bankruptcy is declared.

If a child lives with both parents through the year, either parent may claim the credit — but not both.

Sources: CRA, Ernst & Young, KPMG, H&R Block, Canadian Centre for Policy Alternatives