v>
    </div>

    <div class="ref-description">
    <p>This building block declares an observation model with an additive residual error model (\(y = f + \epsilon_1\)).</p>
    </div>

    <div id="ref-usage">
    <div class="sourceCode"><pre class="sourceCode r"><code><span><span class="fu">obs_additive</span><span class="op">(</span><span class="va">prediction</span>, <span class="va">name</span>, var_add <span class="op">=</span> <span class="fl">1</span><span class="op">)</span></span></code></pre></di