How much bias

Here's a secret: All of it. It's all biased. The whole thing. Even the ones that look like they aren't. They all are. In fact, you're American, yes? If we sit down right now and have a conversation about your conquest of the Philippines...my, my. See there? That word choice? Yep. It should surprise no one to learn that I'm Filipino. Even just that starting point is enough to be a point of bias - or, as will later be explained, a point of perspective.

who gets to decide how history is told?

History is written not by the victors, but by the writers. So it's a matter of who the victors are.

The last few years show that there are several sides to every story.

Apologies for being glib, but that's not just 'the last few years'. That would be the entirety of human history. This business ain't simple - that's why the actual, capital-H Historians earn the big bucks fall into so much argument. (No, they don't earn big bucks. Academia's a total bitch.)

See, here's the thing. History deals with humans. History is created by humans, written by humans, written for humans, studied by humans, interpreted by humans, read by humans.

The inherent problem here is that the human is a stupid, selfish, blinkered creature with entirely too many prejudices, preconceptions, and biases, and a very sharply limited point of view. It is perfectly possible for a human to give a completely inaccurate picture of what is going on without even lying. Historians know this. It's part of the job. It's one of the hazards that the trade deals with, much like restaurant back-of-house deals with the hazards of knives and stoves.

Fortunately, there is such a thing as the historical method, the same way as there is a scientific method. Here are some previous threads for you to consider:

• u/mikedash examines the matter of bias here,
• u/Georgy_K_Zhukov does the same here,
• and u/itsallfolklore considers 'objective history'.

Also, see next post.

I'll echo the points raised in the other comments and also offer the answer to a similar question, "How much misinformation was in my textbooks?":

I know it's frustrating to ask a question and get the answer, "it depends" but alas, that's the gist of the answer to most questions about American education history. The key factor in the case of your question is geography, or more specifically, which state you lived in. Which is to say, there was content in American textbooks in the 1980s that was considered incorrect at the time and in some cases, adults knowingly included incorrect information in service to their own advocacy projects.

[This is] (https://www.reddit.com/r/AskHistorians/comments/b0rzl1/who_decides_what_goes_into_history_textbooks_and/) a much longer answer on the history of textbooks in America you may be interested in but to your question, I want to focus on something slightly different. The first thing to establish is that during the post-Civil War period when education transitioned from the mostly-Northeastern "common" school structure to the nation-wide public school structure, states passed laws and created policies that resulted in each one falling into one of two categories by the 1980s:

1. the state determined which textbooks districts used
2. the state allowed school districts to decide which textbooks to use

With a few exceptions (mostly notable California), the states in group 1 seceded from the United States and joined the Confederacy. The states in group 2 remained in The United States. The starkest difference lies between Texas and New York State. In NYS, any curriculum suggestions from the state have long been accompanied by the sentiment of "adopt, adapt, or ignore." Meaning, the state education department recommends a particular resource and school districts can take that resource and adapt if for their needs, adopt it as recommended, or ignore it. When Texas adopts a textbook, every district in the state must adopt that textbook. This detail is important as it helps us understand the different drivers that shape decisions adults make around textbook adoption. While public education in both states serve similar goals, Texas works towards one additional goal: passing along a state - not just national - identity to students.

Functionally speaking, this means that if you went to public school in NYS in the 1980s, textbooks didn't play as a big role in your education as they would have had you gone to school in Texas. This isn't to say the quality of textbooks in NYS was somehow better than those sold to Texas teachers, just that drivers behind the content was different and teachers' ability to use other resources varied. (In this post, I get into the consolidation of the textbook industry - to be honest, your textbooks in NYS in the 1980s were likely originally written for Texas and then modified for NYS standards. Out goes The Alamo, in goes the Erie Canal.) Texas textbooks would explicitly include content that would encourage patriotism to the state, not just the country.

In addition to geographical differences that shaped adoption or non-adoption status, funding played a significant role. If you attended a well-resourced, suburban school district, you likely had up-to-date editions (new editions were often created explicitly to address mistakes, including outdated information) but if you attended a poorly resourced city school with limited budgets, you likely had to use textbooks that were long out of date. (Related: I explain here how urban high schools in the 1980s were done wrong by Hollywood.) And it wasn't just resource budgets that played a role in the textbooks you would see as a student - it was also professional development budgets. That is, it was fairly common in the 1980s for teachers from well-resourced districts to attend content-specific conferences where they might get free, cutting-edge textbooks and classroom resources to take back to use in their classrooms. This was especially the case for math and science teachers who experienced the consequences of an increased focus on their content areas following Sputnik and the space race. Federal dollars were explicitly set aside for their professional development and even during a spate of budget cuts in the 1980s, science and math teachers were getting together to share resources and pedagogy. (That said, it was still possible to find science textbooks in public schools in the 1980s that included content suggesting some sort of "intellectual design" to the universe but they were/are more likely to be found in private, religious schools.)

If we look explicitly at history textbooks in textbook adoption states, the factor that most likely influenced the accuracy of the textbooks you saw was the presence of the United Daughters of the Confederacy. If they were active, a large percentage of the content in your US history text was likely inaccurate at the time it was written. Karen Cox's book, Dixie's Daughters: The United Daughters Of The Confederacy And The Preservation Of Confederate Culture explores just how influential the women were in textbook content. They played a role in everything from word choice (i.e. "workers" instead of "slaves") to content themes ("The Lost Cause" narrative) to graphics. Although they weren't as active in the 1980s, the students who used the books they influenced in the 1950s were, by then, in positions of leadership and making decisions about which textbooks to purchase.

So back to your question: it depends on where you went to school, how much money your district had, and how invested those responsible for selecting and/or purchasing textbooks were in perpetuating particular myths.