{% extends 'base.html' %}
{% block heading %}Market Structure Lab{% endblock %}
{% block content %}
<section class="panel accent"><span class="kicker">WHAT THIS TOOL HELPS YOU FIGURE OUT</span><h2>How concentrated is the market, and how much weight do the largest firms carry?</h2><p class="lead">You do not need to know the acronyms first. Wize calculates two market-concentration measures, spells out their names, explains what they do, and then tells you what to check before making a decision.</p><div class="actions"><a class="ghost" href="{{url_for('lesson',slug='market-structure')}}">Watch the animated lesson first</a><a class="ghost" href="{{url_for('handbook')}}">Read the handbook</a></div></section>
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<form class="panel" method="post"><span class="kicker">STEP 1 · ENTER THE MARKET</span><h2>Competitor market shares</h2><p>Enter each known firm's share as a percentage, separated by commas. Example: <b>25,20,15,10,7</b>. If the numbers do not total 100%, Wize shows the unentered remainder so you know the picture is incomplete.</p><input type="hidden" name="csrf_token" value="{{csrf_token()}}"><label>Known market shares (%)<input name="shares" value="{{request.form.get('shares','25,20,15,10,7')}}" required></label><button class="primary">Calculate and explain the market</button></form>
<div class="panel"><span class="kicker">WHAT WIZE WILL CALCULATE</span><h3>Four-Firm Concentration Ratio</h3><p><b>Short name: CR4.</b> Add the market shares of the four largest firms. It answers: <em>How much of this market is controlled by the top four firms?</em></p><h3>Herfindahl-Hirschman Index</h3><p><b>Short name: HHI.</b> Square every entered firm's market share and add the results. Squaring makes larger firms count more heavily. It is another way to describe concentration.</p><div class="callout"><b>Important:</b> The handbook warns that concentration does not automatically tell you profitability, innovation, customer welfare, or whether a merger is good. Market definition matters enormously.</div></div>
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{% if result %}
<div class="metrics"><div><b>{{'%.1f'|format(result.cr4)}}%</b><span>Four-Firm Concentration Ratio (CR4)</span></div><div><b>{{'%.0f'|format(result.hhi)}}</b><span>Herfindahl-Hirschman Index (HHI)</span></div><div><b>{{'%.1f'|format(result.leader)}}%</b><span>Largest entered competitor</span></div><div><b>{{'%.1f'|format(result.remaining)}}%</b><span>Market share not yet entered</span></div></div>
<section class="panel"><span class="kicker">STEP 2 · UNDERSTAND THE RESULT</span><div class="explain-grid"><div><h3>What the Four-Firm Concentration Ratio says</h3><p>{{result.cr4_explanation}}</p><div class="formula">Four-Firm Concentration Ratio = share #1 + share #2 + share #3 + share #4</div></div><div><h3>What the Herfindahl-Hirschman Index says</h3><p>{{result.hhi_explanation}}</p><div class="formula">Herfindahl-Hirschman Index = Σ(each market share²)</div></div></div></section>
<section class="panel"><span class="kicker">STEP 3 · WHAT SHOULD I DO NEXT?</span><ol class="steps">{% for x in result.next_checks %}<li><span>{{loop.index}}</span><p>{{x}}</p></li>{% endfor %}</ol><div class="actions"><a class="primary" href="{{url_for('wizard')}}">Turn the conclusion into a Need →</a><a class="ghost" href="{{url_for('reports')}}">Review the project plan</a></div></section>
{% endif %}
{% endblock %}