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"source": [
"## Reverse Scoring Items in a Questionnaire\n",
"In this notebook we will learn another methods for reverse coding of questionnaire items using the R statistical programming environment. Here you will learn reverse coding using a function from the psych package in R. This notebook is for the blog post [https://www.marsja.se/reverse-scoring-using-r/](https://www.marsja.se/reverse-scoring-using-r/) in which you will learn more about this."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Data to Reverse\n",
"As example data, with some columns to reverse, we create a dataframe:"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {},
"outputs": [
{
"data": {
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"\n",
"| Q1 | Q2 | Q3 | Q4 | Q5 | Q6 |
|---|
\n",
"\n",
"\t| 3 | 1 | 4 | 2 | 4 | 5 |
\n",
"\t| 2 | 1 | 3 | 3 | 1 | 1 |
\n",
"\t| 3 | 4 | 1 | 3 | 5 | 4 |
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"\t| 1 | 3 | 4 | 2 | 1 | 1 |
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"\t| 5 | 1 | 1 | 2 | 4 | 1 |
\n",
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\n"
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"\\begin{tabular}{r|llllll}\n",
" Q1 & Q2 & Q3 & Q4 & Q5 & Q6\\\\\n",
"\\hline\n",
"\t 3 & 1 & 4 & 2 & 4 & 5\\\\\n",
"\t 2 & 1 & 3 & 3 & 1 & 1\\\\\n",
"\t 3 & 4 & 1 & 3 & 5 & 4\\\\\n",
"\t 1 & 3 & 4 & 2 & 1 & 1\\\\\n",
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"\n",
"| Q1 | Q2 | Q3 | Q4 | Q5 | Q6 |\n",
"|---|---|---|---|---|---|\n",
"| 3 | 1 | 4 | 2 | 4 | 5 |\n",
"| 2 | 1 | 3 | 3 | 1 | 1 |\n",
"| 3 | 4 | 1 | 3 | 5 | 4 |\n",
"| 1 | 3 | 4 | 2 | 1 | 1 |\n",
"| 5 | 1 | 1 | 2 | 4 | 1 |\n",
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"source": [
"df <- as.data.frame(replicate(6, replicate(100, sample(1:5,1))))\n",
"\n",
"colnames(df) <- c('Q1', 'Q2', 'Q3', 'Q4', 'Q5', 'Q6')\n",
"\n",
"head(df)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Working with the reverse.code function\n",
"First, we are going to install the r-package called \"psych\" and then we are going to sue the reverse.code function to switch the coding of some items."
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {},
"outputs": [
{
"name": "stderr",
"output_type": "stream",
"text": [
"Installing package into 'C:/Users/erima96/Documents/R/win-library/3.6'\n",
"(as 'lib' is unspecified)\n"
]
},
{
"name": "stdout",
"output_type": "stream",
"text": [
"package 'psych' successfully unpacked and MD5 sums checked\n",
"\n",
"The downloaded binary packages are in\n",
"\tC:\\Users\\erima96\\AppData\\Local\\Temp\\Rtmpea2YXQ\\downloaded_packages\n"
]
}
],
"source": [
"install.packages(\"psych\")"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"#### Reverse-Code Variables in R using reverse.code\n",
"Now, we're ready to reverse the items using R:"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {},
"outputs": [
{
"name": "stderr",
"output_type": "stream",
"text": [
"Loading required package: psych\n",
"Warning message:\n",
"\"package 'psych' was built under R version 3.6.1\""
]
},
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"| Q1 | Q2 | Q3 | Q4 | Q5 | Q6 |\n",
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"| Q1 | Q2- | Q3- | Q4- | Q5 | Q6 |\n",
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"source": [
"require(psych)\n",
"\n",
"\n",
"#Reversing scores in columns 'Q2', 'Q3', and 'Q4'\n",
"keys <- c(1, -1, -1, -1, 1, 1)\n",
"\n",
"new <- reverse.code(keys, df)\n",
"df[1:3,]\n",
"new[1:3,]"
]
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